1. Vendor-lock 2. Iffy folder structure. Some stuff both front-end & back-end will live under /pages. 3. Suboptimal experience when you have to use middleware.

1. Vendor-lock 2. Iffy folder structure. Some stuff both front-end & back-end will live under /pages. 3. Suboptimal experience when you have to use middleware. Disclaimer, haven't tried the latest updates, but I assume it's vercel only.