there's more power, (more power = more polishing capabilites) with the VRG than the PC.. i would say that the VRG would be used by someone who's had experience with a random-orbit... not to say a beginner couldn't learn how to use it... i think it's got a longer cord also, which isn't such a big deal to me since i use an extension cord every time... i personally have a UDM, it's pretty much a 7424...

 

Just to make sure you understand the differences here. NXT is a good wax as was mentioned it's full of fillers and will only hide some (not all) the swirling. Zaino is a great product but most often you see people talking about Z5 or Z2. Z-PC is a Zaino product that can help reduce or get rid of swirls but you really need to have a DA or rotary to get the job done efficiently. These are sealants and also will do nothing for getting rid of swirls, not including Z-PC. Removing the swirls through polishing is the best thing you can do because you're then actually taking care of the prob and not just covering it up.

 

Here are the major differences pointed out. As joaquin03 mentioned the Flex buffer has more power, but what does that really mean? The PC has a motor of 3.7A compared to the Flex 7.5A. This means that you can apply more pressure when polishing deeper imperfections without the machine bogging down. This is one of the big limitations of the PC, when correcting deeper imperfections, it simply does not have enough motor to withstand a lot of pressure.

Aside from the motor being twice as big, it also has 60% more oscillations per minute, 9,600 OPM compared to 6,000 OPM on the PC. The Flex also utilizes a forced rotation motion, which generates up to 480 RPMs for maximum polishing results. The combination of OPM and RPM makes it safe for beginners but also effective for professionals.

Here's a great review of the Flex and PC, including a well done video comparing the two.

The PC is the first machine that I recommend to start getting better results when it comes to polishing. After using the Flex next to a PC, the PC will feel like a toy and you really begin to appreciate the power and build of the Flex machine. Other features that separate the two machines are the variable speed trigger. This means you can adjust the speed of the unit on the fly with your trigger finger. This is great in the beginning when you want to spread the polish at a slow speed, then ramp up to a faster speed. It also is convenient when working around corners, crevices and around trim.

One of the cons of the Flex is that it is a little harder to control than the PC at full speed. It has the power to want to walk away from you if you don't have a firm hold of the machine. However, at similar speeds, I do feel the Flex is easier to handle and maneuver because of the hand placement compared to the PC. Price is another con of the Flex, but with the time it will save you to achieve your results, it's worth every penny IMO. You can do twice as much paint correcting in half the time with the Flex (watch the video I linked above for a side by side demonstration).

If you're serious about automotive detailing, you won't go wrong with either machine. However, I'd strongly recommend the Flex over the PC if the money isn't a deciding factor.

Hope this helps.

George