I had a pressure side cleaner for a few years (Polaris 380). Over time I grew tired of higher electric bills from having to run a booster pump, tired of having to clean the debris filter screen what seemed like almost daily, and sick of seeing the Polaris occasionally fly around the pool even though I knew the adjustments were spot on. Regardless, all of that I could stomach if it was an exceptional cleaner. But, aside from doing a good job when leaves were aplenty, it was marginal at best IMO.
A few months ago I, and our wallet, swallowed hard and bought a Dolphin Z5 robotic cleaner. Can't say enough good things about it. Top loading cartridge filtration seems to pick up things that even the eye can't detect. Very easy to clean the filters and pop 'em back in for another go. Scrubs the waterline nicely, negligible difference in electric bill, and picks up more leaves than you'd think it would. I recently had several large trees removed from our backyard and as a result there was a ton of sawdust in the pool. I sent the Dolphin on its merry way, and in a few hours it had it all up. The cartridges were bursting at the seam by that point, but all the dust was there in the shape of a big brick....so it will do a dirty pool if need be. My normal routine is to run it every other day or so, and clean the filters after 3 cycles. Works well for me that way.
After the initial hit on the pocketbook, it's all good IMO. I won't ever go back to a non-robotic.