{Editor's Note: Since I saw these a bit late from their release dates, I combined them.}
Worth A Matinee or Full-Price Ticket: Juno: Matinee. Legend: Definitely Matinee
Will I Own It On DVD: Juno: Maybe. Legend: No.
1) "Juno" is a well-made, small film that features a cast of likable characters (Ellen Page, Michael Cera, Jenifer Garner and Jason Bateman among others) dealing with the consequences of an unexpected teen pregnancy. On paper, this sounds like a potentially putrid Hallmark movie-of-the-week tale, however, "Juno" easily surpasses that genre with wit and a lot of inherent decency from its ensemble cast.
2) That being said, I found the first 10 minutes or so of "Juno" to be extremely annoying as every character was spouting this inane hipster dialogue. Nobody on-screen seemed capable of managing to talk reasonably (or believably), but luckily, this turned around and the rest of the film moved along nicely. 
3) This film also nailed a satisfying ending, a feat that is not easily accomplished as it managed to stay away from a saccharine-sweet conclusion as well as a pitch-black tone that served the story well.
4) "I Am Legend" is a decent popcorn movie that could have been better with less CGI effects (real people, monsters, etc. are ALWAYS scarier than CGI), fewer script contrivances and a main character who was a military scientist yet for some inexplicable reason lived in a humungous multi-story house in the middle of New York City. For some reason, the size of his house really bothered me.
5) The pacing in 'Legend' seemed off as the first act, which mainly featured Smith and his dog, was fine, but the latter half of the movie burned through a lot of issues with very easy resolutions in a quest to get started blowing shit up. 
6) The easy comparison between Will Smith's acting would be to Tom Hanks in "Castaway" as both men were asked to carry a movie alone for vast chunks of screen time. Smith is up to the task as he is always charismatic, however, he lacks the strain of vulnerability that Hanks displayed which made his performance less effective.
All in all, I would recommend seeing "Juno" as I think it might be up for an Oscar or two as it reminds me of "Little Miss Sunshine" in the awards category.
"I Am Legend" is a little dicier, although it's entertaining enough if you don't think too deeply and don't pay full price because the negatives slightly outweighed its merits for me.
-BDS
Yay #1 that's all haha :)
I'd go and see anything with Will Smith in it. He has bucket loads of charisma as you say, not to mention being easy on the eyes :)
Ellen Page was on Letterman the other night, and the interview is on Youtube, worth watching. She is what I wish for young Hollywood, on and off screen! Juno was my favorite movie from 2007!
Agree with you on Legend, the first half so great, not so much in the second .... still love Will Smith!
Miss Ash - Is Ellen Page Canadian? I can't remember but seem to have that in my head. Regardless, she was very good.
Gypsy - Then you'll like this one as Smith is buffed out like crazy. I suppose all military scientists are like this. Ha.
Linda - I need to check that out as I haven't read/seen much about her other than "Juno" (know about "Hard Candy" but didn't see it). As for 'Legend,' I completely agree as it just got semi-ridiculous for chunks of the latter half.
Hard Candy is an excellent thriller. *warning* it even makes ME press my knees together when I think of the unfortunate fate of a sexual preditor. Worth a rental.
great review! whenever the babysitting gods shine down on us we may head to see Juno. NO desire to see I am Legend.
A long standing pet eeve of mine is how characters who make middle income live in mansions and primo apartments. What is the point of rubbing in my face that a government employee lives a WAY better life than do I?
what bothered me about legend was the very clean and polished car at the end of the movie. it actually shone like it was still in the dealership.
28 days was a much better version of the movie, but since i never get to go see movies i can't say i was too disappointed.
The very first time I saw the previews for I am Legend I had no desire to see it. For some reason it just doesn't seem interesting to me. Maybe I have a problem with movies with only 1 character. I don't know. Anyway it will probably be one of the movies I will see when I'm having one of my lazy days on the couch and the remote is in eyesight but not in reach. Hahaha
Linda - Thanks and I'd heard enough about it in that regard that I just never brought myself to see it. I might one day . . .
Vivavavoom - I think you'd like "Juno," so good luck, although it won't lose much in the translation to the small screen and you could wait to rent it too. I'd skip 'Legend' is I were you.
Getoffmylawn - Good. I'm glad others share my irritation as this really bothered my brother and I as it was just asinine. The house must have cost at least $10 million, and unless there is serious fraud going on, a gov't employee would not have that kind of cash.
Cats - Ha. I noticed that too, and I completely agree about 28 Days Later. It was better and scarier than 'Legend' by far.
TrinabeingTrina - I was never completely sold on the trailer myself, although I thought the movie would be slightly better than it turned out to be. It would be fine to watch on the couch one day while dozing in and out of consciousness (sp?).
I know nothing of these two films, but it's nice to see that Jason Bateman has found gainful employment again.
Yes she's Canadian
lesbians love ellen page. as for the dialogue, i agree to a point about the lack of realisticness, but i think her character can carry that level of wit and sass. i just love the opening song.
Heff - Bateman is on a career resurgence (also in "The Kingdom" among others), which is richly deserved after Teen Wolf Too.
Miss Ash - I knew it. Thanks for the confirmation as I like to make sure I'm current.
Kismetic - Interesting. I just read that she's 20 as I had no idea about her age and am terrible at guessing them. That song was catchy, and yes, Page pulled it off. I thought it became a lot more reasonable after the first 10 minutes (Rainn Wilson, who I generally like, annoyed the piss out of me in that opener).
Haven't seen either one yet, but Juno is definitely higher on my list. I can wait until I Am Legend is playing 30 times a week on HBO.
I'm looking forward to Juno. A guy at the theater called it the classier and quirkier version of Knocked Up.
Dear Goddess, $$, SEE HARD CANDY. Stop reading this comment and go rent it.
Now, in case you didn't listen to that order, I am looking forward to seeing Juno but will probably skip Legend because I am privy to the dog scene, eventhough I haven't seen it yet, and think it would not be good. (I acknowledge this is a silly reason to skip a movie but I'm overly sensitive that way. Just don't tell; I have a rep to uphold.) And the size of fictional characters' homes in NYC is always a source of great distress and bother-ed-ness for me.
Why are you still here? You should be watching Hard Candy.
When I'm watching a movie with Will Smith in it, I don't even pay attention to the plot. I just day-dream while staring at that fantastic hunk of man!
I picked up 3:10 to Yuma on Tuesday. Excellent commentary by the Director and a few neat featurettes.
Native Minnow - Yep. As soon as it hits HBO/Showtime/Etc. then you will be able to watch it just about anytime you want. Juno is the worthier choice, although it's difficult to compare the two.
Melissa - Quirkier is a good word for it. It's like an early-stage Knocked Up with less vulgarity and younger characters. Ellen Page is excellent.
BostonPobble - Thanks for the strong recommendation. Ha. I have to work for now, however, I will keep an eye out for 'Candy' next time I'm at Blockbuster. I assume you've seen it, eh? Sorry to hear that you've heard about the dog scene in 'Legend.'
Upset Waitress - Then go check out 'Legend' as you get an extended scene of him working out sans shirt. You're welcome. Ha.
Idig - I couldn't decide about 'Yuma' as I saw it in the theaters and thought it was a solid Western (didn't like the ending very much at all). Thanks for the DVD notes as that might tip the scales.