At AI2 we recently switched to using spray-can as our HTTP client, away from dispatch. Dispatch was great in that it let you get started quickly, and it's backed by the excellent-if-generically-named async HTTP client, but has the disadvantages of:
- backing library is Java, not Scala
- no Actor support (implied by the above)
- very limited feature set out of the box
- documentation is example-based, and sparse
Basically, dispatch is excellent if you need to get something running quickly, but very difficult to use for advanced applications.
spray-can, on the other hand, has great integration with spray-json (which we use for our RPC requests and responses), works well with actors, is pure Scala, and has moderately well-documented code.
The problem is that the actual APIs are often tricky to use. Very, very tricky to use - if the API hasn't been built to support a feature, it can take quite a lot of digging to unearth the right configuration parameter to give you what you need.
Which brings me back to request timeouts.
