[bananas]

The only bad choice was the foundation on which to build the product. The above technologies are pretty much a response to the world being better elsewhere. Unfortunately the responses are pretty immature, poorly documented with bad support reputations and virtually no backing.

I've used most of the above. ServiceStack was pretty good but nothing in comparison to Jasper which has much better documentation, a cleaner architecture, stable migration notes and better performance. Look: https://jersey.java.net/documentation/latest/index.html

NancyFX I haven't touched.

NHibernate is a buggy behemoth with a learning curve from hell. It doesn't scale well with project size (we have 2000 tables of which about 500 are NH mapped "model-first") and it stinks. The SQL generated is terrible, it's impossible to debug when it goes wrong other than sift through 50Mb of log4net DEBUG level logs. To add insult to injury, the LINQ provider is so buggy it's like programming with a hand grenade. I've used hibernate in java and NHibernate isn't even a tenth of the way to the maturity and reliability.

Dapper - I really like Dapper. I have used it for data transforms before. However it doesn't play well with low trust as it uses IL emit.

OrmLite - see ServiceStack.

Not bad choices - just choices I either regret or had to make because the whole ecosystem is amateurish outside of Microsoft and unstable inside of Microsoft. Sorry.

[pbz]

Have you tried LINQ to DB (not LINQ to SQL) the successor to BLToolkit? We've had good results with it, but we like to keep our queries and datalayer as simple and thin as possible.