Menzerna polishes are my favorites by far, with the exception of power gloss. Yet, with a random orbital or the Flex forced rotation random orbital hybrid, I wouldn't recommend using heavier compounds anyway, so the polishes are great. Might I suggest PO83 Super Intensive Polish (PO85RD3.02 aka "SIP"), PO 106 FF/FA Nano Polish, and the new PO203A Power Finish. I can't forget to mention 3m ultrafina, either. Be sure to not use to much, and to let it break down properly. In terms of compounds, I prefer 3M Perfect-It 3000 Extra Cut, Megiuars 105, and Menzerna S34A Powergloss at third.
Regardless, a rotary finishes better because it properly breaks down the polishes as even the flex cannot 100%. (Although darn close, and it does an excellent job). Being new, you may want to start with the flex.