I have a Queen Quilter 18, which is apparently a sister to the Tin Lizzie. It didn't come with very good instructions, so I've had to do a lot of research on my own to learn how to thread it, oil it, and use it! I've only had mine for a few months, so I'm probably not the most knowledgable one to give advice. I would never buy one without the stitch regulator. It is nice to have a uniform stitch no matter how fast or slow I go.
My frame is the Gracie whatever wood frame. That was a bugger to assemble. Directions were awful. We had figured it would only take about 2 hours to build. Nope. Took us 8 hours! My husband is an Electrical Engineer and pretty good at building things, but this was not a fun project. I would not buy this frame again.