General consensus is that Chima isn’t all that great, although it has some redeeming elements. I’m not a huge fan of the bug sets in Galaxy Squad, but that doesn’t mean nobody is. Different strokes, as they say.
Are you talking about buying for yourself, or for trying to sell parts and figs, or what? Either way, you can’t buy all the deals; if you’re trying to sell, it helps to have a bit of a game plan (i.e. – diversity is great, but it’s not worth it to just buy a few Friends sets to get pastel colors, because people need them in quantity… so maybe pick a couple themes and concentrate on building useful quantities of theme-specific colors and parts before you worry about diversifying too much…)