I am sure you will hear much from others as well; here is my take on it -
Really nicely designed, ergonomic, and the on-off switch and speed control are right by the hand you use to hold the body of the machine.
It seems louder than my PC 7424 or my Meguiars G110V2, but then it does have forced rotation and a bigger motor/
It does awesome correction work but I personally like to use my Rotary to correct, and then come in behind it with the Flex 3401VRG to finish with something like Meg205, etc., and or jewel with something like Menz PO85RD.
I didnt care for the handle arrangement on the top of the buffer, so I got a side handle for the Flex from another site that sells them and they're pretty inexpensive, so it was a no-brainer. I learned with the side handle way back when, and I will always like it on big machines that have forced rotation.
Little machines like the PC or the Meguiars G110V2, I dont have any handle at all on them..
It tends to run hot on the backing plate if used a long time, but it supposedly has sensors to turn it off if it overheats, and it has not turned itself for me yet.
Only drawback so far - it only accepts the 6.5" L/C pads,----------------
BUT with Gary's experimental modification posted today (GEWB), it appears that you can cut down the foam and backing plate hook and loop material and attach a 5.5" pad on there, and according to Gary, it works and runs much smoother and easier with the smaller pad!
I really like the Flex because of the forced rotation feature and its been a good machine for my needs and if the modification that GEWB did to his backing plate holds up, then you could now have an even sweeter machine that would accept the 5.5" and 6.5" pads if you bought another backing plate, and modified one of them like Gary did.
I am currently looking at the lighter of the 2 rotaries that Flex sells - the 3403VRG to have as back up for my Makita 9227C...
Good luck with your search -
Dan F