Rm2k3 actually has some functions new makers only provide with scripts, like fog, 8 direction passings settings, and more layer passibilty.
You can do a ton with it, you just can't script. Custom battle systesm, menus and the like need to be evented.
The RTP doesn't really look good imo, but there is an ungodly ammount of awesome ressources around for it, if you don't mind the lower resolution, it's really good, especially if Degia would rework and completely translate a few features.
Personally i wouldn't buy it simply because i got it like 10 years ago, before all the legal trouble came up, it was even published and promoted in video game magazines back then.
Shouldn't really change the fact that that version is still illegal, but hey, things were different back then and you won't just throw something away that you bought once.