I've had some experience with a FeatureBase "board" for another app I use, and while the follow-up questions on upvoting were a useful feature, on the whole I found it significantly lacking compared to Canny. Most significantly, that app's feedback board didn't have any kind of categorization, so finding any existing suggestion (even ones I myself had made) was hit-or-miss depending on whether other unrelated items using similar keywords came up first in a search. Canny isn't perfect, but (as an end user of the app for which Canny or FeatureBase is the issue-management platform) all of its issues (in my estimation) are ones that FeatureBase either shares or has a significantly worse form of.