Due to politics the MVP had 2 false starts at other agencies before the third company built it in a crazy short timeframe. The third company was only going to built Android/iOS apps to an API specification provided to them, but ended up doing the entire backend too.
The false starts were down to lack of clear guidance as to _what_ the client wanted from the agency and very slow feedback loops regarding progress. The first attempt was absolute overkill (and very slow velocity), the second attempt was nothing like the intended idea and development stopped after 12 months. Runway was getting shorter so third agency built it.
The biggest mistake was the client hiring a fresh junior as their first in-house developer, and them not having sufficient experience to identify parts of the platform that would become obvious scaling problems. Later on these became very expensive problems!!
Despite unflagging and upvoting, I still don't see this in the ask section again. Certainly didn't mean to negatively impact your question's progression. Hopefully @dang or @sctb can restore its position.
Very sorry about that!
So yes - experience with hiring agency - all negative.
Given you're asking for an MVP I'd suggest you make it smaller. There are tons of ways to learn about your customers' problem and whether you can solve it for them without writing code. We've built landing pages using Keynote which we then tested with customers, ran entire processes that were supposed to be automated manually, and even prototyped a machine learning algorithm by manually coming up with our best guesses for a users' search query. Because the purpose wasn't scientific validation, the purpose was learning. All these three we built in a day. For more: https://hackernoon.com/the-mvp-is-dead-long-live-the-rat-233... http://paulgraham.com/ds.html