I have one of the Motive power bleeders and I use it regularly.  They are
the tool of choice for those who do bleed brakes often.  I haven't found any
downside to using one, and I've perhaps done hundreds of brake bleeds.  When
I raced, we often bled brakes a couple of time per day at the track.  We
always used the 'different color fluid' method to make sure we got totally
fresh fluid to all four brakes.  ATE Super Blue/Gold are my brake fluid of
choice.
  My only problem with these is the tubing used to connect the pressure
vessel with the system in the vehicle is prone to degrading and gets all
'rubbery' in a year or so.
  Don Hanson