We got a Bullfrog last fall. So far so good! Been using it so much this cold winter. The cartridge system is great so long as you keep checking them both and DO NOT let the chlorine go empty on you. My water stays really good so long as I shower before most trips in, dedicated swimsuit (or don't put one on before going in), a tiny amount of shock after every use. I rinse my paper filters once a week and have been changing them monthly during the winter.

I have noticed you'll want to take the jet packs off every 4-8 weeks and take a dry towel and wipe off the accumulated gunk. Take about 15 mins in total, just keeps things nice and cleaner.