I really wanted to like Unity, it was pretty easy and smooth to work with... but the free version's limitations just grind on me (and I had an experience with the free version failing to do what I wanted to do before as well, so its not just hypothetical). In fact, the entire thing looks like its setup to constantly upsell you and drain away as much of your cash as possible thru sneaky methods (but I guess at least theres the store for content creators and such, plus a somewhat established base of plugins easily accessible). If you just want to make games without caring about all that though, and can keep it from grinding on your nerves, its a perfectly fine engine.
Though, if you are releasing a commercial game you should be able to afford the premium... sometime AFTER you release your game... but you kinda need premium before you start making it.... (and I guess this is where the $75 subscription they are offering would come in, though its of course much higher than the alternatives right now)
Of course, there are ways to get premium beforehand, but then you are already playing with fire, and if you are doing a group project it may be in danger (like, say, someone refuses to work on unity premium before they've actually payed for the license to use it, etc aka this happened).
Imo, these other options sound like a much better deal. It seems like it would be best to start on Crytek on a non-commercial license, then once your idea and team is setup (and theres dedication to actually finish and release your project) swap over to the subscription plan. Since theres apparently now Cryengine for Linux in the works, that covers crossplatform too.
Of course, if you wanted full source control and modifiability, the unreal 4 path would probably be the better option (at a pretty decent cost though, comparatively, at least if you sell your game later). That said, most of the work likely has already been done so mucking around with the direct source is probably going to be moot. It might make a good learning experience though for aspiring developers... or just anyone curious (I might grab the source one month when I'm bored and have time <like that ever happens anymore> and read over it, might even learn a few things).
And of course, Unity still wins in the web plugin front I guess, which as far as I know these others wont ever touch.