I'm not up to date with the latest developments but upon the release of V3 the author (it pretty much is just one guy) made quite some "not so clever" decisions. With V3 he pretty much started to rebuild the engine from the ground up while abandoning the V2 version while also not delivering certain features meant to come for the V2. He also had some "insane" price wishes for his new work. This lead to many in the community being quite angry at the development as they wouldn't get the desired features / fixes for their V2 version and only could buy a quite overprized V3 which had less features than V2. The author then had to packpedal and adjusted the price to a more "sane" value...

I don't know if he was able to introduce the features he did promise back than but I wouldn't really recommend the engine. It was pretty interesting but the backsteps in features with V3 together with the way he introduced V3 doesn't make the engine's future look too promising. He's also not the only guy working on an engine. I also didn't like the new editor that much - it sort of looked "cheap" and wasn't that rich in features. The only intereseting aspect was the visual scripting part but that's something you can find in e.g. UE4 too or via plug-ins for Unity. I'd rather have a look at the Neoaxis Engine. It just like Unity uses C# for coding / scripting and you can download and use a full version of the engine in order to try it out / use it for non-commercial purposes. I especially was impressed by the enormous number of feature demos / demo scenes you can play and investigate in terms of how it's done...

One also could have a look at the upcoming Shiva Engine 2.0. They have the absolutely worst PR I've ever seen though with endless delays with usually zero communication with the community / the early adopters. The company pretty much also went out of business for a while but now seems to be back on their feet and actually finishing the new V2 of their engine which now is years late. Especially the editor seems to feature an ease of use and adaptability just like for the one Unity has. If its features are convincing and the pricing remains reasonable (right now you can get for a very cheap price as an early adopter and also use the old V1.9.2 engine) this might become quite interesting...