Well, I use Simplify3D with Smoothie and it currently seems to be fine. I had a few hang issues before, but not since updating Simplify3D to v3. You just *do not* want to ask for help with it, at least not in the IRC channel.

I wouldn't wait for the new smoothieboard. It comes up in the IRC channel fairly regularly. The board developers simply will not commit to a promise date. It probably doesn't help that there will be, as I understand it, different versions. The "pro" version will have an FPGA core on it too yet. It has been apparent that there's been a major push on smoothieware firmware evolvement this year. It could be that the developers wanted that TCO first in order to establish a fairly solid baseline that would then be migrated to the new board, but that's just me guessing.

True, the current v1.0 smoothieboard may not be pushing the current envelope, but it's farther along the evolution path than an 8-bit Atmel ATMEGA processor with a RAMPS shield.