I've had the TAZ 6 for a little over a year. It's been great - no problems with the bed, quality of the print was very nice, and even had several 2 day prints. Would have given it 5 stars across the board.
A few months ago, the LCD started to act squacky - as if a phantom was pushing the knob jumping from screen to screen. Called support and we diagnosed it was probably the LCD board ($68). Ordered it, installed it and things looked like I fixed it. A few days after warranty expired, it started again. Contacted support and had several e-mails that really didn't help solve the issue. Contacted the Lulzbot forum to no success.
Finally, support suggested the problem was 1) the LCD board AGAIN. 2) a short somewhere in the wiring harnesses, 3) software that suddenly changed behavior, or 4) the RAMBo ($170) board failed. #4 seemed the logical choice so I ordered it, installed it and after 2 months of no printing (and it's amazing how dependent I became on my printer!) I'm finally printing again. I also had to upgrade CURA to flash the eprom on the RAMBo. But the good point to make here is the excellent documentation online to support an adventure like this with the TAZ 6. I'm not an electrical engineer but I was able to handle this one.
I'm still impressed with the "open-source" nature of this product - all the printed parts and available in STL form, along with documentation the explains how to fix it. This reminds me of working on PCs when the PC clones were first available.
The TAZ 6 is not cheap (nor is the TAZ Workhorse or TAZ Pro), but I've been happy with product and would recommend one if the budget can handle it.