48 is a lot harder, faster, and less dwell time than Rhyzm-P. Lower throw also.
I haven’t tried 50.
I’m currently using Rhyzer 43 (max) on backhand. More control than 48 but less control than Rhyzm-P. 43 feels more like a 45 degree rubber. Speed is much faster than Rhyzm-P. Similar speed to MX-P (maybe a tad faster).