As I'm working with UE4, I'll try to be unbiased as I can.
I'm also going to go right ahead and assume you are a solo dev.
Unity - I haven't messed around with this engine so I can't really give you concrete feedback on this, if my memory serves me right, the engine has been available to the public for awhile now so there's a strong community around it, just check the forums/asset store (paid/free) and you'll get a feel as to how big it is. As far as making games out of it, It's a tad bit easier to learn than UE4.
RPG Maker - I've spent little time on this back in 2012? Didn't like it too much, as it didn't allow me to do what I wanted. Very simple to use though, as you only need to draw 2D sprites(Textures) and place them around. As you didn't have to worry about 3D models/animations and the nitty gritty stuff that makes your characters sing in a 3D environment. Can't say much about this since I've never touched it since then.
UE4 - As I've spent most of my time learning this engine (roughly 5 months), this will have more information on it. This engine is a beast, and just like any beast it's going to take some hard work to tame it. As stated above if you're a solo dev, this is going to be an extremely rough road. I can say with 100% confidence it's going to be rough. As I'm currently a solo dev working with this engine, yes it includes doing/learning everything (Coding/ 3D Modeling including all the sub-text below and the texturing)
Unity/UE4 requires you to have some form of knowledge in
Coding
3D Modeling not limited to (Rigging/Animating/Texturing/Modeling)
Audio (Unless your game has no sounds)
Texturing
Well, rpgmaker gives you everything you need. Unity and UE are not made solely for RPGs, so you'll have to put in a lot more work and they usually are worse when it comes to performance.
If you chose rpgmaker, don't chose MV.
Use either XP or VX Ace. They're waaaaaay better than MV.
Also look for scripts online to make your game less cookie cutter garbage.
I agree to disagree, Unity/UE4 does requires more finesse to get good performance, you can't just willy nilly just start throwing stuff into the engine and expect it to start spitting out god like performance. There is continuous optimization that needs to be done throughout the project, but the topic of optimization itself is a whole different topic so I won't elaborate on it.
In my honest opinion I say try to learn Unity/UE4 and stay away from RPGmaker, Unity/UE4 allows you do do what RPGmaker does but with more tools at your disposal.
Best of luck to you.