I’ve had mine for several months, and while I have gotten some good prints out of it, I am not a huge fan.
My main complaint is the weight, specifically that it is cantilevered out in one direction from the x-axis rods. The rods are already undersized to begin with, the additional weight of the dual head causes problems. It would have been nice if the weight was at least centered on the x-axis rods. (There is a fix - Piercet’s openrail mod, which I will eventually get to. Also I understand that the Taz6 has bigger rods).
The problem is so bad that if, while you are aligning the head, you lift up on the front of the head and then let it back down, it will assume a new height. It makes it difficult to consistently level the head front-to-back.
The other huge problem that I have run into is that while it will print PLA pretty well for a while, eventually it will start to fail due to heat creep. I don’t know why it got worse over time, but it did, and with both extruders. I don’t believe the solution to this problem lies in more air across the existing heat sink; if you look at the thermal interface between the heatsink and the filament tube, you will see that the heat sink does very little to remove heat from the filament, and heat traveling up the filament is the basis for the heat creep problem (which is why it occurs most prominently with PLA). I added a second blower to the heat sink and it made no appreciable improvement to the heat creep problem. I am currently testing another solution that looks very promising, I will share my results.
I think that if you are seriously considering a Dual Head V2 you should also budget for the open rail mod on the x-axis. If you are planning on printing with materials other than PLA, you should be OK.