For those who say YFII has a vibrant community, you need to understand the emission schedule of YFII. The halving schedule happens on a weekly basis, and all the YFII will be distributed after 10 weeks. I very much doubt the project will continue to have a community after the yield farming for YFII is finished.
With only 10 weeks of emission, YFII is clearly not sustainable. They cannot mint more tokens as the admin key is burned.
Edit: include the emission schedule