I was in exactly the same positon as you a few months back.
I brought synthmaster, as I'm a student and I qualify for academic version £37.
So far, I've only found a very few obscure things that I can't do with it (FM/AM with more than 2 operators and partial shifting). Also has a fair few FX in there too, not amazing quality but as good as you're gonna get for a synth.
If you aren't a student, it's £61.
I haven't got anything to compare it with though. Zebra looks like a good bet, but it's twice the price, £120.