Mesh lets me gather all of the rain over the winter to replace my high alkalinity fill water. A big plus. I have to drain the pool a couple of times over the winter, but I just stick a hose in the skimmer and run it down hill to drain back to the skimmer level. In the spring, I just don't drain it, and I open with the water near the top of the skimmer, which is good, because by the time you backwash and vacuum, the water is right.

As to dirt, mine looks like about three times what is in there normally when I vacuum, with clear water. I can't imagine the hassle of pumping off a solid cover would be worth it, but this probably depends on your location and climate as to how much winter rain and how much dirt blows around.