Julie
My company does alot of shop and field based cabinet grade finishing...in both primer/paint and stain/clear combos.
We have had very good look with the Festool orbitals. We do not use Rotexes much in this application, mostly because of weight, balance, cumbersome in carcasses, and difficulty in one handed use. The orbitals are made for this. The ets 125, rts 400 and dts 400 are all good choices, and all can double as small drywall patch sanders and other uses.
On dye and clear finishes, after spraying first coat, any of the ets/rts/dts are great to float for scuff sanding. With clears, all you are looking to do is dull the sheen, smooth it off and create just enough abrasion for the ensuing coat to enjoy good adhesion. Granat abrasives (320 grit, give or take, depending on situation) in higher grits is ideal because it doesn't load, or therefore scratch, which in turn is a tribute to the superior extraction that the smaller sanders, by design, have. Hand sanding on clears is very difficult. It can be done, and with good results, but its just more efficient to have a system of sander/abrasive/extractor to take some of the risk and time out of it.
As others have noted, and this is critical, with the orbital sanders, because their extraction is so strong, it is important to turn the vac extraction way down to keep the sander from getting rowdy and turbulent on the surface. At low extraction and high speed on the sander, fine finish sanding goes pretty smoothly. Another important consideration is to be sure that your first coat of clear is well cured before sanding. Product comes into play big time in that sense. With lacquers, we can turn it around in about 25 minutes. With other products, it can be 24 hours before it is safe. Once you know these variables, things become simpler.
Please keep us posted. Time to boot that mental block. Good luck.