Speaking from Experience, expensive moisture wicking shirts can still smell.

The secret is to try and wash the shirt right after your workout, or at least the same day. If you can't, let the shirt lie flat, do not let it bunch up or throw in a pile.

You want to shirt to get dry as soon as possible. If it sits all bunched up, say in a hamper, the moisture will cause the shirt to stay wet, and the smell will build up. This problem happens with every kind of fabric.

Also, you should avoid shirts with prints on them. Like a big logo or a silkscreen design. The smell gets caught in that, regardless of the shirt material.

I personally prefer the cheap 100% all cotton shirts with no logo. The cotton feels good on the skin. The moisture wicking shirts are okay if you are working out for hours, like if you were running a marathon. But for a 1-hour CF class, I prefer the comfort of cotton.