I'm on a well too, and I struggle with alkalinity in my fill water. I guess it is better than metal. The backwashing water loss is an issue with DE or sand. I've considered Slime Bags, which claim to be able to clean your backwash water enough to discharge it back into the pool. Whether that would be less trouble than cleaning a cartridge, I don't know. http://www.cleanerpools.net/

I've never dealt with a cartridge on well water, but I would be a little concerned that it might struggle with the mineral levels in your water. If you have neighbors with pools, I'd ask around. I have used a cartridge on an AG pool on city water, and it seemed like I was always cleaning it or replacing it. I would recommend you price replacement cartridges before buying a filter, and condsider having a second cartridge on-hand so you can delay the cleaning if it clogs at an inopportune time (this is guaranteed to happen) or you have exceptionally dirty water (like an algae bloom) to clear up.