I agree, if you are using a PC, #105 will probably be your best bet on hard clears with lots of defects...and #105 actually works well by hand for spot defect removal. I haven't use #105 myself with a PC or UDM, but my Meguiars distributor said they played around with #105 and the new Meguiars DA buffer (G110?) and with a burgandy cutting pad, they were able to quickly remove 1500 grit sanding marks.
With the rotary, I really like Optimum Compound. Decent defect removal and minimal holograms.