Worth Full-Price, Matinee or Rental: Unless you are absolutely starved for a bit of comedy, then I would suggest a rental for "Step Brothers" (and only pay matinee prices if you venture to the theater).
Will I Own It On DVD: Not unless it ultimately goes on sale for $4.99 at Best Buy, and even then, I would have to be feeling flush with cash.
1) The law of diminishing returns has officially set in with Will Ferrell playing stunted adults with a penchant for random sayings (you could argue this had already occurred with "Semi-Pro," however, I have not seen that film.) There are still funny lines spouted by Ferrell, but you can almost feel him working too hard to come up with them versus his past performances where they felt fresh and effortless.
2) I'm also getting tired of what I call "concept comedies." In this case, I could picture a producer selling the movie as "Will Ferrell and John C. Reilly play grown men who still live at home with their single parents. Then, their parents get married and both men move in together, share a room, and feud with each other before becoming best friends. Hilariousness ensues."
The problem is that very little work is put into a reasonable script as it feels like they simply turned the camera on, and allowed Ferrell and Reilly to riff and improv at will. 
3) That all being said, Ferrell and Reilly are both funny individually and also boast a fine comedic chemistry together. This was first seen in "Talladega Nights" and there are definitely several laughs sprinkled through the relatively brief running time (90 minutes) thanks to these men.
But I'm starting to find it disconcerting to watch Ferrell and other comedians pushing 40 years old and above playing such hoplessly stunted adults. It was a lot funnier when they were close to 30 years old, however, it seems a bit sad these days and something which needs to be left behind in the near future. 
4) Richard Jenkins and Mary Stenburgeon (sp?) were very good as the parents of Ferrell and Reilly. Jenkins is a master of the slow burn, and his patience is constantly tested by the ridiculous hijinks of his 'boys.' Stenburgeon looks great, and always has a nice empathetic nature to her which works well here.
5) "Step Brothers" was one of the most vulgar comedies I've seen in awhile. There are no characters present who don't toss of "fuck" like it means nothing at all. This is probably why I saw some parent take their 10-year-old son out of the theater and never return.
-BDS
I have NEVER spent money to see a Will Ferrell movie. I'm kind of proud of that fact.
I've never liked Will Ferrell as I just don't find him funny. Judging by the reviews for this film, people are slowly figuring it out for themselves. Maybe it's time Will Ferrell put his pants back on.
Improv comedy groups get tired pretty fast. The Christopher Guest series really only yielded two funny films in my opinion.
Did you see "Walk Hard"? Another movie that almost was funny and very crude. I love Will Ferrell, but I've always thought he was better doing skits on SNL - it's hard to make an entire movie out of one joke.
I'm a big fan of Richard Jenkins and I'm glad to see he's getting work.
Heff - Then this should't be the first one to break that cycle. Ha. Old School is actually pretty funny if it comes on cable.
WhatIgot - I liked "Best in Show" a lot, and "This is Spinal Tap." "A Mighty Wind" was OK. As for Ferrell, this movie opened pretty big (30 million), so I might be in the minority here.
Anonymous Boxer - I did not see "Walk Hard." I almost rented it several times, and in general, I like Reilly quite a bit. I completely agree about Jenkins as he's always good in every role I've seen so far.
I want to see this movie, but probably won't until hit comes out on DVD, or plays on HBO. Admittedly, Will Farrell doesn't have to try very hard to get me to laugh. That said, I did see Semi-Pro, and the schtick is starting to get old.
I actually wanted to see this one....
And also that other one about the war movie with Robert D. Jr. It looked tres funny. You should review that one :)
Native Minnow - I agree with your comment up and down the line. Ferrell is a funny guy, but maybe it's the sheer quantity that he's released the past few years, however, something has to give - at least for me.
H. Wood - Are you sure that wasn't in the deleted scene extras on the DVD? Ha. I could believe it as I do remember the bear stunt from the trailers.
Miss Ash - It's not horrible, but if I had to pick between "Step Brothers" and "Tropic Thunder" (your Downey reference), then I would go with 'Thunder.' And yes, I plan to see that one and will review it. ha.
Was it that bad? That's a shame, I like a good comedy every once in a while... but I guess this wouldn't be a good choice.
I do like Will Ferrell, haven't seen all a majority of his movies though.
I tagged you - it's not bad, I promise.........
Grace - I wouldn't say it was terrible or unwatchable or anything like that, so if you go in with low expectations then you'll definitely get some laughs - especially if you haven't seen that many Ferrell movies as my main criticism is that he's repeating himself.
Anonymous Boxer - I have a tag streak to keep intact, so I will definitely answer it . . . thanks.
ok, my favorite ferrell movie is stranger than fiction and i wish that he would do more movies like it because i honestly don't like any of the rest.
and why do people take their young kids to movies before looking at the rating? i had this problem with the batman movie... there were kids younger than 10 at that movie and i can't imagine that they didn't have nightmares afterwards.
Thanks for the review. I had free passes to see this last week and couldn't bring myself to go. I've had it with the man-boy antics. After the disaster that was Semi Pro, I just couldn't make myself see this one. Renting Anchorman to remind myself why I think Will Ferrell is funny.
I like Ferrell and Reilly, but I agree that enough is enough. You can't run a concept into the ground and keep pooping out comedies. I agree with what Cats said about Ferrell and also liked Reilly in "Magnolia" very much, a somewhat serious role.
Cats - I agree 100% with both points. I just had that same exact discussion around 'Fiction' with my brother this weekend, and I also thought the same damn thing about 'Batman' as that is not appropriate for young kids in my opinion (to be fair, I don't have any of my own).
Linda - Wow. I might have taken the free passes and gone. Ha. That would probably have been worth it for $0. And I almost watched "Anchorman" (own it on DVD) on Sunday to remind myself of the same thing. It's a shame, eh?
Jlee - Those are both good films, although "Magnolia" is a bit long for my taste (and Tom Cruise was actually great in that one too). Anyway, this concept has run itself into the ground for me, but if you find this on TV some lazy afternoon, it might be worth tuning in for a few laughs.
why do you people think will ferrel is so bad? he's really funny. i spent 9.50 to go see this movie in theatres on a saturday, and it was definately worth it because i was laughing through out the whole movie. if you don't think this movies funny, then you seriously have a very good sense of humor. yeah i didnt really want to see will ferrel's stufffff, and it was kinda stupid at times, but it was real funny! i tell all of my friends to go see it!