With baby #1, we never used a heavy bottom stay put plate for self-feeding. We ended up losing a lot of meals and learned to make at least double the quantity baby would eat. This time around we're thinking about introducing one of these plates - just to save on the grocery bill! We like the orb-shape of the slip-resistant Saucer by Boon.
The Saucer has a base that grips the tabletop, so although not a guarantee of no-spills, makes it more difficult for babies to toss everything overboard. And as is the standard these days for mealtime goods, it's BpA-free, phthalate-free, and PVC-free. Get it here.