The OP is used to a “regular” RC looper, like I was.
I was totally upset with PU at first and made all my first recordings with Flex playback.
PU are very confusing, especially for overdub, you have to press 2 different buttons to start/stop overdub. If you press them twice, you can replacd recording or stop playing ! 
After yesterday other tests, I don’t think I would use PU in live conditions.
They are better than Flex for overdub, if you want to layer sounds, better to handle long loops recording. Less clicks.
@crumblecakes, for the best of 2 worlds and more freedom, I would use both OT and RC. If you want to control with your foot, RC 300 is better than RC 50, much more logical, no track select.
RC 505 is more advanced, especially with the V2 update, I’d recommend that one or the RC 202. You can control them with 2 footswitches, or a midi foot controller.