GIFs are great at producing solid, consistent color......
the quality degradation comes when trying to
reproduce photographic continuous-tone images.....
since 1 color needs to be on a sperate layer, theres no qual. loss.....
more and more printers these days support the TIFs w/transparency...
but not all by a longshot...anytime u are going to be printing
u should be talking to them about procedures (in which they print,
how they like their files, if their press/printer uses a special color profile ect)
for their company anyway; thats just how most
of my t-shirt printing has resulted......