I have also owned a pair of Cheng's boots. Great construction, great fit (felt like houseshoes!).
I currently own a pair of JW boots. Sizewise, they're a bit tighter, but very solid construction. The only thing I don't like is the mis-matched sole. There's a layered piece of sole that appears to sit awkwardly on top of the main sole, and sports a lack of attention to detail on the part of the bootmaker. I'll probably be able to correct most of it with sanding.
I cannot speak for the accuracy of either of these, as I haven't done enough research. There are some boot gurus on the board who can better point out the accuracy pros and cons.
Either way, I've been satisfied with both pairs. In my opinion, you can't go wrong with either one.
As for the CA Boots, they are much cheaper (and at this time, the only ones readily available), but there are some noticeable accuracy issues, even to the average Fett costumer. However, I have seen some outstanding CA Boot 'makeovers'.
DISCLAIMER: Members that are able to acquire the MC or JW boots need to remember and understand that neither Mark nor Wes actually 'made' the boots, but rather thet were the contacts and project managers, so to speak. Any commentary on the shortcomings of the boot construction are NOT directed at these fine folks, but rather at the those who actually put the boots together. I know for a fact that JW went through hell in both time and money to make sure his orders were completed (including a trip cross country to pay extra to get the remaining orders). From what I understand, MC had some of the same issues with his boot-maker as well.