learning ruby will be more engaging and valuable than virtually anything else you can do inside the RPG maker programs so choose one of the newer ones. it's also cross-applicable to web development (make a cool site for your game!) and general computer programming, which is a valuable skill for any game developer. they have basically all the features of the old ones, as far as i know so you can ease into it. i think that the rtp graphics are vaguely nicer, but making your own is a lot of fun too. (easier to do when you wrote your own game program though!)