I picked up my 45 Watt Mini 24 Friday evening. We immediately set it up and began to tinker. The unit itself is much louder than I anticipated. It moves a metric-ass-load of air over the heatsinks. I haven't gotten a DB meter and shot it, but if I had to guess it'd be in excess of 65db.
When using the rotary attachment, make sure your round piece is smooth on the left side (the side that will end up against the bumper) otherwise your engraving will have irregular edges.
Figure out a way to index your work piece in the machine.
Keep a small stack of shimming material around for "irregular" items.
Using a flatbed scanner to place/tweak art is a godsend. Seriously.
Experiment, Experiment, Experiment.
*more later, I promise.*