Robotic pool cleaner for our Big Old Pool

The original pool on our farm was built in the 1950's and had 50 degree spring water flowing in at one end and out the other end. 35 years ago we made the pool a bit smaller (75x35x 9.5deep) by building a new pool inside the old pool. It now has proper filtration, and gets a bit warmer, but we are tired of using a manual suction pool vacuum to clean it and are looking for a robotic cleaner. I have done some goole research, but would like recommendations form actual users of robotic cleaners. It needs to do the bottom and sides. Our pool also has a ledge around the deep end to stand on when hanging on the sides. Will a cleaner go over that ledge and up to the top of the pool, or just drop to the bottom at that point? Also the bottom has been painted many times as is not a very smooth surface. Will the cleaner scrub or suck out all the little particles that get stuck in the little holes in the surface? We want a cleaner that is reliable, easy the clean, easy to maintain, and while we can do some mechanical repairs, has a good service network. Thanks in advance for any advice.