Personally, I've been really enjoying my 21J Noobmariner. It cost $65 shipped to the US. I wanted to get my feet wet at the low end of the spectrum.
As mentioned, the better movements get you a smoother sweep. Is it worth it to you? The other issue to think about is that once you have a sub on your wrist you and pretty much nobody else will see the small details people talk about on the forums. On my sub the rehaut rengraving isn't correct, the pearl material sits lop-sided in it's housing, and the Rolex crown etched on to the crystal doesn't line up exactly with the six marker but you can't see anything of those details without a magnifying glass. (see attached magnifying glass shot). Do you see any of that in the small pic?