If the cost is the same or very similar, get both. This way, you can do things like have both of them open at once, and work on one while rendering in the other. Plus, some features have been rebuilt in P13 (something long overdue) and may still be unstable, so you might like to have P12 to go to when that happens.

If it's pricier to get both, just go straight to P13. There are no backwards compatibility issues for any type of content or plugins so you wouldn't be really missing anything.

- - - - - - 

Feel free to call me Ohki!

Poser Pro 11, Poser 12 and Poser 13, Windows 10, Superfly junkie. My units are milimeters.

Persephone (the computer): AMD Ryzen 9 5900x, RTX 3070 GPU, 96gb ram.