We stayed in 8550 and honestly we didn't care for the location much! I realize we are in the minority here but we didn't care for hearing the chairs from the pool above us scraping around, we didn't like the fact we could hear kids running above our heads at anytime, we didn't like the fact that the sailaway parties at night were so loud that our kids could hear them and couldn't go to sleep so we had to crank up the sound machine just to drown it out. It was nice to only be down 1 level from the pools but the main elevators were always busy, it was hard to get one at "peak" times during the day so we ended up doing a LOT of stair climbing. We also stayed in 8504/8506 and while I hated the pitch and roll of the front it was nice for elevator catching.
Just my .02 but I don't think I'd ever stay midship on deck 8 again. It seemed very noisy and annoying to our family.