The accessories included
Depending on your needs, it's a good idea to check which accessories come with your food processor. Common ones included are a dough hook, shredder disc, whisk, and universal knife. Less common accessories are a citrus press, egg whisk, meat grinder, and different cutting and chopping attachments.
For tips on when to use a food processor (and when it's better to leave it in the cupboard), have a look at this guide.