There's nothing to be frightened about. While MVC is known mostly as a pattern for separation of concerns, it's also routing system based on convention. The convention is very easy to understand and it dovetails nicely with exposing web services.

IMO, it's far easier to understand how the plumbing for MVC works than it is to understand how WebForms work.

As far as "lock-in" is concerned, you should be more concerned about lock-in using WebForms. WebForms depends heavily on ASP.NET web controls. With MVC using Razor syntax, you use standard HTML mark-up. It's far more like PHP than WebForms mark-up.