I have noticed better overall health to MY plants since switching to plastic. Not saying one or the other is better.
My thoughts are mainly for the life inside the pot. The plastics seem to be more uniform and the soil stays damp a little longer which gives me a little bit of a break. In smarties I don't have an extra day it needs to be watered when it needs to be watered. This is just observation by me I will still use them but I am trying out other stuff. The plastics have some advantages, and so do the smarties.
One of the main reasons I use plastic is because I can bleach them between runs if I get PM, rot, gnats, etc. Mind you I've got none of those....except a few weakling spider mites that do no visible damage and maybe some thripes from time to time. But if something got out of hand and I had an outbreak of PM.....I'd be worried the fabric smart pots would transmit the mold spores easier. That could be mitigated by putting empty smarties out under the sulfur burner....but then what would that sulfur do to the roots?
I avoid that with plastic.
Plastic rootmakers.....now that's an intrigueing idea.