Recommending an MRX over a powerflarm is like recommending a flip phone over a smartphone. If powerflarm is too overwhelming for you, you will still be safer if you turn it on without ever looking at it than if you use an MRX, since it will warn other gliders of your presence. After the earliy PCAS issues were resolved, I continued flying with both MRX and my PF brick (with butterfly display) side by side for another 100 hours or so and here are my unbiased observations:
1- PF has better reception most of the time
2- altitude difference is always correct in PF. It can be totally wrong in MRX almost half the time especially after flying close to someone else it seem to confuse the altitude calculation for a while.
3- MRX will sound an audio alert too late most of the time as it only sounds an alert when the traffic is 1 mile or so away. PF with the latest butterfly firmware will sound a short alert whenever it detects a new traffic within the max distance you configured.
4- MRX has reliability issues. Mine went back to the factory more than 5 times over the 5+ years I used it. To Zaon credit they never charged me and have an excellent customer service.
Disclaimer: I am not affiliated with neither Flarm nor Butterfly.

Ramy