Anyway, remember: each version has its strengths and weaknesses. There is no one that is better overall over the others (Except in the cases of 2k3 and Ace which are enhanced versions of 2000 and VX, respectively). The best option depends on your project. The language you plan to use, the mapping style, resolution, and the ways you plan to distribute. I still use Ace and 2k3 myself and they work very well for my choices.
If you're new to the RPG Maker softwares I would recommend to pick up RPG Maker MV. It's the latest RPG Maker version out there currently. VX Ace and MV aren't that different, but they have some slight differences. Unless you absolutely want a certain feature that's unique to VX Ace, I would suggest MV.
RPG Maker VX Ace is the older version with Frontal view Battle system. RPG Maker MV is the Newest version which supports built-in Sidebattle system. Also, VX Ace is a lot simple to use while MV would seem a little more complex if you are New to RPG Maker Software.