I'd be interested in hearing your opinion as a comparison - what are the pros and cons of each?
Have you swapped back to the MS?
Back to MS, more due to personal preference than anything else.
Pros/Cons there aren't a huge amount.
ME221: Easier to order, faster to arrive
Phone, email, ticket based support
Marginally better basemaps
General purpose tables ( Alllows you to control any output either on/off or PWM based on any combination of 1/2 inputs)
MS2 ( and MS3 to a degree as Reverant no longer produces any MS2 units):
MS2 Cheaper (MS3 same price maybe £50 more)
Support for Oil temp and pressure inputs - CELs on MS2, CELs and limp mode on MS3
MS3 has native USB, SD card logging, traction control
Subjective but better software
While support on the ME221 is better, I never needed any support with MS but there is plenty of information all over forums etc.
I had some issues with ME221:-
Overboost protection when triggered wouldn't re-enabled spark until ignition was cycled ( Fine if you set it to cut fuel only, likely a beta firmware issue)
I found their closed loop fuel control, auto tune and the Long Term trim feature to be less accurate and stable compared to the Autotune in MS. LTT would be killer if it worked as well as I'd like as you wouldn't even need a laptop connected to correct fuel tables.
Closed loop boost control wasn't as accurate as MS (Admittedly I'm expecting a lot more than most people with the way I taper additional boost in past 5500rpm) but it flat out ignored the inital duty table ( possibly beta firmware related) which meant it would either not maintain boost targets, wildly overshoot on spool or osciallate horribly.
For 99% of people I'd recommend the ME221, they aren't going to be worried about any of the things I didn't like as they're going to fit it, load a basemap and drive to a tuner. If I was building another from scratch I'd stick with MS