If just to repaint bumpers & skirting, normally I just go with the cheapest, as long as the color matches and shiny enough then I'm happy! The last time I just went with a Groupon deal for only like rm100 per panel to repaint my skirting.
Why so? Because bumpers & skirting will often get scratches and chips again (especially as my car is also lowered), so I never want to pay much for those.
For body then may consider better quality ones, but normally I'm also not that particular with high quality expensive stuff like Glasurit etc2. I'm always looking for reasonable value for money stuff. But I'm very particular on the color matching, really itchy to even a slight difference in shade or metallic reflections.