Well? Which is a better groupset and why? Difference I shifters? Etc.....

The Alivio line of products is better than the Sram x4 by far (in my opionion). The Sram x4 is found on department store bikes, the Alivio is found on higher end bikes. After reading a few reviews on the Sram and Alivio, the Alivio reviewers are generally more pleased with the shifters than the Sram owners are.

I totally disagree. Having used both, the x4 works better IMHO. I'm running it on my Inbred 1x8 setup now. You can replace them dirt cheap( 25.00 LBS) and they work fine.

I think that it's awesome that you couldn't figure out how to use the Sram stuff.

Alivio on higher end bikes? I don't think so. BTW, Alivio IS found on some department store bikes, i.e. the better ones, but they are sold by Target.
As for X4 or Alivio, At this level, I'd give the nod to Alivio, butif you're buying new, I'd recommend looking at used higher end SRAM. I was a huge Shimano fan until I rode a SRAM X-9. Now I've got two SRAM equipped MTBs.

Alivio is now 9spd. You can find it on some pretty nice bikes. I'd say it's a wash between the two in terms of precision (if you can figure out how to shift them). My preference is Shimano but you can't really go wrong.

that was funny, but not at all accurate. he knew how to use it. he simply didn't like two thumb triggers compared to one thumb and one finger. I don't like two thumbs either, but I could possibly get used to it with time.

my bike has sram twisters, which I love. maybe that other guy should have tried twist grips before selling the bike.

BTW, the Alivio rear shifter will down shift 1 or 2 gears depending on how far the thumb lever is pushed (based on the PDF file docs on the Shimano website). I just bought the Acera SL-M310 trigger shifters and although the documentation lists a two gear down shift if the thumb lever is pushed for two "clicks" and detents, there are actually 3 clicks and detents, allowing up to 3 gears to be dropped in one press of the thumb lever. Surprise! Wonder if the Alivio does the same.

With the Acera dropping 3 gears with a press of the lever, I am able to go from 7 th to 1st with just two presses of the thumb lever. Every bit as fast as a twist grip can do the same.

I had a chuckle at that too...

I just rebuilt an old Trek 6K with Alivio DRs front and rear and an Alivio crankset with an SRAM 8spd cassette (it was on sale).
Running SRAM twist shifters, I couldn't ask for it to work better thus far banging around town. Quiet, shifts quick enough, and
it was cheap. If I had planned to abuse it offroad often I might have read more, and spent more, but I'm very pleased so far.
It's certainly better than what Trek put on this bike thirteen years ago.