Hello. Does anyone know if the M200 is any good? Right now I can get it for the same price as the S200 and it's supposedly better built being an M series. I'm demoing an M400 right now and it's doing an 'ok' job with my pool. Won't climb the walls (but I'm pretty sure they have accordions filters in there). I'm worried getting the M200 will be much worse than the M400. Thanks.