So, here's my dilemma. I have a quad that is strictly a midnight flyer, uses the Runcam Night Eagle Pro V2. The FC currently in it is a Beerotor BRF3 with onboard MinimOSD and I'm looking to put the FrSky R9MM and GPS antenna. The installed BRF3 FC has an on board Baro, and the Omnibus F4 PRO & Betaflight BFF4 boards I have laying around don't have the baro sensor, is it worth changing over to an F4 FC since I rarely fly it and when I do its just for nighttime cruising?

If it's flying the way you like and you don't care about being on the latest version of Betaflight with the latest features those new releases provide then I would probably just leave it the way it is on the F3 board. If it's not broken then don't fix it.

If however you want to make use of the more recent features of Betaflight 4.x then you will need to be running at least an F4 board because F3 boards have less features under BF4.0.x and were dropped completely from BF4.1 (unless you are happy to use the unsupported/untested versions of Betaflight 4.1 for F3 boards which were compiled by Mark Spatz' HERE).

Mark disabled GPS functionality in 4.1 for F3's. That trumps no baro on the F4's, so an F4 it will be. thanks for the info!