@Nick , a raft through the Grand Canyon is one of the most wonderful experiences we ever had, i recommand it to anyone!
The scenery is breathtaking from begin to end, and, in case that is also important, there are enough serious rapids to get the adrenaline flowing, especially the day after passing Phantom Ranch (Horn Creek, Granite, Hermit, Crystal, and of course Lava Falls later on.
Having no experienced and lucky (after winning the lottery) friends to invite us, a commercial trip was the only alternative, you hardly need any special stuff of your own.
The food was excellent on both trips and the guides do most of the work giving you time to explore a bit before dinner or around lunch.
For me the scenery was the most important part, and by taking a trip labelled as "hiking special" you have the best possible option.
We did an 11 day Motorized trip and, another time, a 14 days oars trip (there were a few people with their own kajaks as well on the latter).
The 2nd trip was almost a present as we got it as 2 people for the price of 1.
If you can get on a longer trip, just do it, it's awesome!
We did many hikes into side canyons and to higher places, one referred to as "the death march" went up to Thunder River, over Surprise Valley and than back down to Deer Creek.
There are also tons of beautiful places like Elves Chasm, Matkat, Nankoweap, etc. for shorter breaks and Havasu Canyon if you are lucky.
One time when we stopped to set up camp, we were surprised with an loud "bang". After a while we figured out that at the other side 2 bighorn males had a fight on a narrow ledge. After each "bang" they went back a little bit and grazed for maybe a minute before the next "bang".
After about 30 minutes they suddenly stopped and peacefully went up the slope to the herd that had been waiting higher up.
Both trips started at Lees Ferry, the 1st one went all the way to Lake Mead, the 2nd we were taken out at Diamond Creek.
The 2nd trip we also had a partly exchange, some people only took a half trip and hiked out at Phantom Ranch and some new people hiked in.
(There are also trips where people are taken out somewhere at the end by helicopter).
I think the Company you go with is less important than which guide happens to be the Trip Leader, he rules and decides where to go and where not, as we found out when the guy just refused to go where the Company Owner had specifically assured us several times we would go.
Just a practical advise, when you want to be assured to have beer to the end of the trip you better bring 10-15% more than you plan to drink yourself as on both trips we had a few people that happily drunk the beer of others.