Yes it goes on top of almost everything (not Vinylux)
I like OPI, but I also use China Glaze when I find a polish I can't resist to. Also Essie because it's very popular here, although I much prefer the others.
CND are also amazing. CND Vinylux is a special professional system that doesn't require base coat.
Also CND Creative Play which was only recently launched is your usual laccquer.
Nubar Nail Art stripers for nail art.
Choose a brand and stick to it. Google their colors and just go with whatever you find more convenient to you concerning their range of colors, ability to find and price