Good Morning Steve,
Elite (714) 895-1911 has been around for years. The best bang for your buck in my opinion. With minimal tooling you can change over the unit in about 5 minutes. They even modified the platen for my print nest at no extra charge. The only thing I don't like is the squeegee that ships with the product, I went to Transition Automation (800) 648-3338 and got a steel squeegee.
If you want a semi auto unit (requires house air) look for a used De-Hart. There isn't much that can go wrong with these units so they are a pretty safe buy used.
Hope this helps,
Dan