I've been using one of the original dual extruder Makerbot Replicators a lot (owned by my school's science department-- currently in my living room, heh); in terms of reliability, it's about the same as my Prusa... but, when my Prusa breaks down, it's always been because I've done something completely stupid (ie short the 5v line on a stepper driver to the 12v one...), whereas the cause of the Makerbot breaking down has been a mixture of me doing stupid things and design flaws, most notably the annoying delrin plunger they use in the extruder.
The Makerbot seems more rigid but print quality's about the same -- only ended up spending $285 on my Prusa with a coupon code, though, whereas the Makerbot sold for something like $2k....
ToyBuilder Labs has refurbished dual-extruder Flashforge Creators for $850, by the way:
http://toybuilderlabs.com/everything-else/refurbished-flash-forge-creator