I’ve used it as my main app for the last couple indoor seasons. The videos I tried during my free trial were much better than the rouvy videos I tried during that free trial. I found rouvy videos to be all over the map quality-wise, some were nicely filmed on bikes, others were clearly from cars or motorcycles and looked bad when slowed down to riding speed.
The latest version of fulgaz isn’t very stable on windows. The program freezes during pairing, sometimes just randomly clicking on things can cause it to crash. Apparently a new version is due to be released soon and hopefully it fixes some of the bugs. I had version 4.3x installed previously and it was much more stable.
I think they’ve the best videos out there, though they don’t have the geographical variety that is on rouvy. Most of the videos are mostly from the anglosphere and western Europe. They are however all very well edited and aside from their Ironman and avatar rides that use CG riders overlaid onto video, all the regular videos are filmed on bicycles so the leaning around corners looks realistic.
It works well with the kickr climb, though due to quality of work they put into the videos, it’s always matched the on-screen hills, unlike my experience with rouvy. Both programs are better with the climb than zwift was.