A floor frame definitely has a learning curve. Once I learned to use my thumb to quilt, I found the frame much better to use than a hoop, but that's me. One thing to remember is that a floor frame needs a lot of space - mine is the size of a living room couch.
Most hand quilters I know prefer a hoop. I have a Grace floor hoop, too, but I did not care for it. I recently purchased a Jasmine floor hoop on eBay, and it seems much nicer to me. I haven't used a sit upon hoop, so I can't help you there.
Good luck with your decision.
Janet