The swings are really not a big deal. I have a #3 and get swings, but they average out and I will put my results up against any Auber smoked results.
For certain low temp smokes like for fish or jerky, the level temps are a little more important. But, I would try without it for awhile before you spring for the Auber.
Don't get me wrong, the Aubers are great and definitely have a place. The programming capability is really cool. I just wanted to make the point that they are not needed to produce outstanding BBQ.