I've been doing my nails since I was in 2nd grade, so it's safe to say I know a thing or two about nail polish and what I like, haha.
By far my favourite polish brand is OPI. Great selection of colours, excellent formula and great brush. I do agree, sometimes it seems like each new OPI colour collection has repeats of the same ol' reds and pinks, but there are always stand-out shades that I haven't seen anywhere else.
The 3-free formula has gotten way better, which makes for a very smooth application. And I like the Pro-Wide brush, but I imagine it might not be the best for ladies with smaller nail beds.
Lasts a very long time with base + top coat. Not much else to say...love it and will continue to purchase.
China Glaze isn't sold around here, unless it's hiding and nobody has told me! I'm aware of e-tailers that sell ChG but I'm not a fan of ordering things online. I would love to try one of their holos.
MAC polishes...most of the ones I've tried are much too thick for my liking, even right out of the box. I don't like having to thin them out right away! The brush is OK.