Cinnamon, 64 bit. But I used MATE before, and saw no difference in Gramps.Did you use MATE or CINNAMON? Thanks.
1. Mint 15 RC is a Release Candidate. That means that it's not consumer ready, officially speaking,
2. Spell checking, handling image data, and geography (maps), are not available in a clean Mint install. Gramps works well without, but installing these features is quite a technical task, which can only be done when you feel comfortable with stuff like this: