I have a Felix 3.1 dual extruder and personally I don't think that having dual extruders decreases the quality of the print. Both extruders have to be set at pretty near exactly the same height to get good results, so find out how easy easy it is to adjust them should you need to.
One thing with dual extruders is that there is a penalty for using both extruders on the same print. In order to stop the extruder that is not in use dripping onto the print, it's left to cool off by 40 degrees or so while the other extruder is being used, and has to be heated up again when you want to use it. This means the printer is waiting for the extruder to heat up every time the extruders change over, although it usually alternates which extruder is used first on each layer to minimise this. On longer prints this can add quite a bit of time.
Al