Have a read of these two threads, they mainly stayed on topic and some give their feedback. I settled on Rouvy (which i consistently type Rouby) for the reasons stated on those threads.
https://www.bikeforums.net/indoor-st...rides-now.html
https://www.bikeforums.net/indoor-st...rides-now.html
i think both are good but i liked Rouvy more, partly because i liked the UI better and i liked that i could add virtual riders and my own previous ride if i repeat a route. there are a lot of routes to choose from. Some of the Rouvy routes are crap in my opinion becasue the grade simulation is not granular enough or does not match what is on the screen. For Rouvy's AR type routes this is nt the case, only the ones that are put up by the community (not sure how to do that). So far, i've ridden about 30 routes in Rouvy and all but maybe two were shot from a vehicle. all of the FulGaz rides i did were shot from a bike. I think the bike videos are of a better quality becasue they are traveling at...bike speed. Both will speed up/slow down the videw based on your performace, and since nearly all ROuvy rides are shot vrom a vehicle this means they are all typically slowed down, only an a descent or two do i notice it being sped up.
i came from zwift only because i got bored with the same old rides over and over. i stil zwift from time to time (did one last night) and like it but not enough to pay for it. cost of Rouvy is on par with zwift - 15 or 14 $ per month and can temporarily stop at any time. I did the tree trials of both Rouvy and FulGaz and would recommend you do too. they ran for two weeks. i think FulGaz still lets me ride with some limitations like maybe one or two routes.
Don't forget RGT. more like zwift in that it is all cartoons but very limited routes. their big thing is magic roads, it allows you to send them a .gpx or .fit file and they generate a world for you to replay the ride. not available in the trial but i got the idea.