My quick comparison between the two in various areas:
Exterior visuals: Nothing to choose between them here really, both very nice. The BR one comes with several liveries and has lots of liveries made by repainters available. The 40th Anniv. IniBuilds Goose only has one livery included (I am not counting the “aviators club” ones), hopefully repainters will give it some attention. The IniBuilds one currently has an error where it has no reflections cast on the water. Winner: Even
Interior visuals: The BR model is a military JRF so it has a much more spartan cabin while while the IniBuilds one has a more plush civilian cabin. Unless that matters a lot to you, nothing much to choose here. Winner: Even
Flight modeling: The IniBuilds one uses the newer CFD and prop modeling whereas the BR model does not. The IniBuilds one requires noticeably more trim to counteract engine torque. In theory the IniBuilds one is more realistic, although I am certainly not in a position to comment intelligently, it’s not like I’ve flown a Goose in real life. Winner: IniBuilds (although the flight model of the BR one is certainly not bad)
“Usability”: The IniBuilds model has no radio or navigation equipment of any kind and the developers have told people to just use the VFR map. It’s representing a 1937 as built, in theory. The radio range navigation equipment used then has long since been retired in real life and is not operational in the sim (although there are some third party mods for it). The BR model has a hidden GPS console you can use if you want. The IniBuilds one is also much more difficult to control on the water because it requires differential engine power to steer, as in real life, but differential throttle in the sim is iffy right now and many people will not have peripherals with more than one throttle axis. The BR model has “invisible” deployable water rudders to aid water handling for this reason. Some will appreciate the commitment of the IniBuilds model to realism, others will find it simply impractical. For me personally… Winner: BigRadials
Sound: The IniBuilds 40th Anniv. model has strange, persistent but seemingly random squeaking and chirping sounds in the cockpit which may be annoying to some. The developers have said they are reviewing it. The engine sounds are also, IMO, significantly less throaty and “convincing” than those of the BR model. Winner: BigRadials
Of course, you have to consider all of this in light of the fact the BR rendition is $25 and the 40th Anniversary one is free.
If you are a huge fan of the Goose I think buying the BR one is still well worth consideration. I have owned the BR one since it came out and it’s what I will probably continue to fly. If this is the type of aircraft you’ll only fly once in a while, the IniBuilds one is certainly good enough, and will probably be improved in the future.
I wish that the IniBuilds model had represented a modernized cockpit so that both renditions fit their own niche, but that may not have been the brief that was given by MS/Asobo.