I got my orbital from Griot's garage. It was $129 and it comes with a pretty cool detailer's handbook and a DVD. I haven't used the buffer yet or watched the DVD.
I know griot's used to sell the porter cable and then switched to their own brand. Apparently, the new one is lighter than the porter cable.
2013 F30 328i - Melbourne Red
2011 E90 M3 - Monte Carlo Blue
2004 E46 M3 - Imola red