Hi, guys, I'm interested in best practices in using of each approach. Personally I like MonadError because it is more explicit and Control.Exception-s becomes really ugly in complex scenarios. Here an example to illustrate my idea: http://hackage.haskell.org/packages/archive/network-conduit/0.4.0/doc/html/s.... All network-conduit functions can raise IOException because of Socket-related stuff (and actually entire network-conduit is written to deal with IOException correctry) + Bind-port can raise ErrorCall (came from error "bindPort: addrs is empty"). User has to deal with both, but have no evidence on none of them from type signatures or documentation. Moreover, ErrorCall in this case can be caused by IOException (we try to bind only available address, we get IOException exception, we have no more address to try and raise ErrorCall), and I really don’t understand, why it should be treated in a different way. So, I hate exceptions, I blame it, I think exceptions is junk came from OO-world and horrible languages like C# or even more horrible like Java, and it should be wiped out from Haskell with fire. But it is only my humble opinion. Reality shows that Haskell provides extensive support for exceptions, it included in base libraries and everyone uses it, but MonadError is modest part of mtl, and don’t even have “bracket” and other useful functions. That is why I’m really interested in any your ideas and experience on using these approaches. Cheers, Stasik.