I have an Xp3 and a AC110 hob on my 84g and love the filtration it gives me. I use two powerheads to blow detritus towards my filter pickups and the water is very clean. It's up to you to decide how you want to set it up. As has been mentioned, take into account noise, ease of maintenance and turnover rates. Make use of our reviews section to read what others have experianced with thier particular filters and go from thier.
12x the turnover is great but 8x the turnover ain't bad. It all depends on how you set it up and how crowded your tank will be. For most cannisters remember that thier flow rate is determined running empty without any media in it. The more you add the less it will flow and as with any filter the more detritus it picks up the less turnover rate your going to get from it.