Polyverse is a decent omni-genre system.
It's well written, and there's a definite focus on the mechanics of the system, which is more than I can say about a lot of these.
However, I'm not necessarily heads over heels for the art, and to be honest I could pass on most of it.
There's a lot of content, the page formatting doesn't make eyes bleed, though it doesn't necessarily do any awesome stuff, and it's pretty uninspiring. The tables are clean and concise, though I saw one place where I'm assuming they meant to put "damage" in after some of the rolls (i.e. for the effects of an radioactive environment).
It's good, and it's cross-genre, so if you need a quick system to do anything, you can use Polyverse, especially given that it has a deep focus on mechanics that leads to a high-quality game.