Pretty much like asking is nrs or hyside better, both are top notch companies and you can't go wrong either way.
AOTG=tons of money, super nice facilities, everything is maintained very well and nice. Close to town, much shorter Gauley shuttle, great guides to work with, they can keep you busy. Great restaurant and bar on property. Shuttle for new river is close and easy, not a lot of bus time.
ACE=they are down in the little town of minden, so much more isolated. During high water the put in for the new river is on property, super short shuttle, Gauley shuttle sucks 1 hour plus each way, best lower Gauley take out saves on several miles of flat water. Lots of money and great facilities, everything maintained nice a great equipment. Restaurant and bar on property, but a big advantage is the campground. It's huge as in 1700 acres or something, all guides live in sunset (on property) so it's guide village, cuts down on the drinking and driving, free camping but most guides tend to be more isolated because everything is their they tend to not leave the property. They also do a lot of other stuff on property, climbing trips zip line paint ball mt. Bike if you have skills in these areas or want to learn them they are all about cross training guides. I can't even remember how many miles of trail their are on property but it's a lot.
One thing to remember it's way different then Colorado. One trip a day, you will know your schedule at the beginning of the week, but these places are huge with 100 plus guides on staff so they don't tend to put up with things like being late or giving away trips a lot, or just being a dumbass. Matter of fact at ace if your late by 2 minutes your bumped for the day, do it three times and your out of a job. If you want to take a weekend day of during Gauley season you have to take the whole week off.
Look at their websites, see what's the best fit, if your doing it it's always better to show up in the spring before all the trainees in may. You can't go wrong with either company