What are the differences between the different brands, such as performance, durability, parts available for repair in the future. Right now in my area the ones available are the Carvin laser, Hayward sand filter and Hayward Pro sand filter. I have used a laser before but when the multiport valve started leaking the whole valve had to be replaced, but the Hayward has more replacement parts so it would be a cheaper repair in the future, but Hayward's cost more upfront, and I have herd that the new tanks have manufacturing problems and the tanks tend to break or leak. Is the quality different in the different brands or are they pretty much the same.