There were 2-3, or more reports about 1-2 years ago, in which the Flex backing plate got real hot/overheated, and little bits of plastic spewed everywhere. The recommended fix is to lubricate the felt ring with compressor oil or something like that. There have been 2, maybe 3 reports of the internals going bad on nearly brand new Flex machines. The distributor and retailer did right and stood behind the product.
Peeps that own & use the Flex swear by them. I used a Flex once, (my buddies) and I swear, I never got it past setting #4 There is no doubt that the Flex offers without a question, superior performance over the PC, as the backing plate has forced rotation, whereas the PC does not have forced rotation.
At this time, I'm not doing a lot of details on cars other than my own. My car looks hella bling, bling, achieved with PC. So, for now, I'm staying with PC.
If Flex offered a 5'' backing plate, that would be a major incentive for me to step up to Flex if I decided to go that route in the future. I just feel that, for that kind of money, a consumer should not have to lubricate a felt ring, and keep an eye on it with usage. The idea to lube the felt ring came from I think the distributor, or AG, not sure, but I just feel that the manufacturer does not have it completely dialed in. The manufacturer should of been the one to explain lubing the felt ring, not a distributor, or a retailer after 3-4 backing plates disintegrated.