Vortex Sound Research

I've been producing a few years now and I really wanna get my hands on an analog synth, I've kinda been obsessing over Moogs for a while now and I'm thinking of buying one. My question is what's the best one to buy? I've heard the mother32 is a good starter but can be limiting, my choices now lie between the sub37 and grandmother probably. I don't have loads of knowledge in this area so some guidance would be appreciated.