Do consider a digital system as well. Given the great performance of typical digital cameras with ambient light and/or built-in flash, as well as the wide focal range of their lenses, it might be a viable alternative. For about what you'd spend on these other systems, you could get a good digicam and housing, and add a strobe later. Lots of folks on this board can give you some great advice along those lines.
Of the MX-10 and Reefmaster, the MX-10 is much better, as other posters have explained very well. However, the MX-10, like other systems, suffers from having a strobe too close to the lens, which causes backscatter.
I'd gather as much information as possible, take your time, and make a very informed decision.