I just recently took the leap to more serious detailing tools and products... but the last "pep boys" three step I bought was the Meg's Ultimate you mentioned, worked with my Craftsman Orbital with Microfiber pads. Like you said the compound does a pretty good job in making the car look a lot more swirl free, in normal light. Followed up with the Ultimate polish then wax and it looked much better.
After I washed it a lot of the imperfections came back in the same place, so that led me to believe that there is a lot of filler in these products
and that I needed a buffer upgrade bad (just bought a flex 3401=hell...yes)
The reason why it didn't come off easy was that you probably used to much, worked to big of an area or let it dry which are no good for compounds and polishes. I actually enjoyed the ease of use and the cleanliness of the product.
PS - Try it on your headlights it makes them look real good.