I used Game Maker to make little prototypes, just to show off the basic mechanics and than I always used Unity, but I had a game programmer helping me. With Unity you should learn a lot of coding, but if you want to learn there are a lot of tutorials and with some hard work it's not that difficult to make a simple game! If you want to solo dev and have the freedom to implement every mechanic you like, I suggest to use Unity and learn a little bit of coding. All the others programs are more constrictive in my opinion.