After market rims for 2014 SQ5

I am considering buying after market rims for my summer tires on my 2014 SQ5 so I can leave my winter tires on the original rims.
1.) Anything I should be aware of when looking at after market rims!
2.) I am considering buying these: NICHE M117 MATTE BLACK WHEELS FOR 2014-2019 AUDI SQ5 - 21X9 25 MM - 21" Does any one have experience with them?
3.) Any experience buying from ProParts USA?

Thank you.