@pikim No, I am not. My original plan was to deploy more and more RFM-based nodes as they seemed superior over NRF24 in general, but I realized that my NRF24 network was rock solid and reliable, so there was no need for the added complexity and cost to support and integrate another transport. Plans are made to change them.
That being said, I used the multiRF gateway for months without issues. The gateway operated as stable as the single transport 2.3.2 gateway. No issues at all, except with the automatic TX power adjustment (ATC) of the RFM transceivers, due to what I believe might be a timing issue within the library. I described the issue in this thread. Basically, the RFM nodes were not able to reduce their transmit power, unnecessarily blasting the environment and wasting battery power. Introducing small delays in various places was all it needed to work around this issue successfully, seemingly without adverse side effects.
This issue has not been properly remedied since the introduction of the multiRF gateway though. For all I know, it is still tekka's personal fork of the MySensors 2.4 branch and has not been updated, so any new fixes and features for version 2.4 since March 2020 will not be available to this fork, unless you manually implement them.
So I guess it is up to you if you prefer to use the multiRF gateway without all the mainline 2.4 changes, or the up-to-date 2.4 branch without the multiRF feature. It should not make much of a difference currently, according the the commits since the multiRF fork, unless you want to use PJON transport or deploy NRF5-based nodes.
I really wish that the development on MySensors revives, as it is feeling kinda stale at the moment. It would be a shame if this project got silently abandoned. I would be glad to help out wherever I can.