After using heat transfers for several years I have found
that simple one or two color heat transfers work well on
images that aren't to complicated and have nice clear
thick lines in the text and the design.
Screen printing works out better if you have a small
front left chest design that has detail and several colors
and then the larger matching design on the back.
Screen printing will also work better IMO if you are
doing multi-color designs with great detail and depth.
An example would be a Guy Harvey shirt with their trademark
The cost factor on transfers goes way up once you add
several colors and you will need to order a large amount to
get a good price on the transfers.
When we ordered multi-color transfers from a large transfer
company the amount of plastisol ink always seemed to get
thinner and the design on the shirt wouldn't last as long
as screen printing.
There are companies out there selling stock heat transfers
that are old and have that "Plasticky bandaide" feeling to them. You
find them at fairs and other events and you can run your
hand across them and see exactly what I am talking about.
Heat transfers do work out great for certain designs because
you can press them to order and won't have to keep numerous
screen printed shirts laying around keeping your revenue tied
Hope that helps.
This is an example of a design that I would never think about
having made as a heat transfer. I don't think any company could
make a quality plastisol heat transfer that would get this detail
and made to last.