Mountain Biking - New Rear Derailleur

I just broke my Shimano Alivio derailleur on my trek 4300. Couple questions. First, should I just replace with the same model? Is there a better one available for around the same price? Any advice is appreciated.
Thanks

Use this opportunity to go SRAM! Gotta change the shifter too though.
My bike build was kicked off my a broken derailleur. X7s are incredible value.

sram rear derailleurs are better than shimano. shimano moves all over, movement means less efficiency and more chance for breakage. sram move less. this is because of the way they are built, i could explain but it would take too long and you wouldn't really care. instead, here is video proof...

http://www.youtube.com/watch?v=AZQf1bduGYs

There's nothing wrong with Shimano drivetrains. That vid doesn't show me anything valid like which one will ghost shift or which one will cause a skipped tooth. It's a hoax video to help Fred feel better about spending so much more for his X.0.

OP: Save your money and replace it with an LX or SLX RD. I've installed and used X.7, X.9, Deore, LX, SLX, and XT. They all perform admirably. My own experience shows me that XT will outlast X.9 consistantly with regard to the main pivot. X.7 is a sweet setup, but if you already have Shimano shifters...it's not worth the coin to change it all. I've been running Deore shifters on the Crapper for a while now (dual release) and they're still nice and smooth.

LX is pretty bombproof and I have really liked all the XT's I have used... the only rear d that has caused me grief was an older XTR who's lower jockey exploded on me.

Find an older Deore and you will be happy... these are really solid.

There's nothing wrong with Shimano drivetrains. That vid doesn't show me anything valid like which one will ghost shift or which one will cause a skipped tooth. It's a hoax video to help Fred feel better about spending so much more for his X.0.

...

i wouldn't normally disagree with you, i'm sure you know waaaay more than i do (this is not false humility and sarcasm, i'm serious, i don't know crap) but this time i will disagree with you. i'm not saying shimano is bad, i'm just saying the SRAM rear derailleur is better than the shimano rear derailleur, and i say this based off what i learned at STU. yeah, i know STU is laced with propaganda, but they made sense.

I think we're all forgetting that "better" is often an opinion. The impression I've gotten is that SRAM performs better at any given pricepoint, but Shimano will outlast SRAM in terms of durability. I can vouch that in my experience, SRAM X7 shifts smoother & more efficiently than Shimano Deore, & same for X9 vs XT.

BUT, not better enough to be worth dishing out the extra cash for new shifters, IMO.