Our VP540 is coming up on two years old and still on it's original print heads, I think most of the clogging issues is people using cheaper non-oem ink, we were warned against using non-oem ink by several people when we bought our printer.
Very reliable.....never a clogging issue, but to use a Versacamm to print tee shirt vinyl IMHO is a waste of the printers capabilities, that said we use to do printed vinyl shirts, never liked the feel (hand) and bought a DTG printer to do tee shirts. Our Roland spends it's days printing vinyl signage, decals, banners, vehicle wraps, etc which is again IMHO what the machine was meant to do.
Sorry can't help you here......all I can say is all the printed heat applied vinyl we applied to shirts always washed great, I still see some of the shirts we made over a year ago and the colors are bright with little or no fading.
Hope this helps.