Depends on your criteria. At this time I feel like React has a larger ecosystem (assuming there isn't a lot of incompatibilities with v16), and there's a clear path to mobile if that's a choice. Vue seems to be a simpler programming model, and makes it easier to iteratively build. Personally I'd say don't make a choice at the beginning, but build a simple version of your app in both (say login and 2 or 3 pages) and make a decision based on that.