It depends on what you're looking for, of course. There are certainly a few unique features that are very nice (e.g. type providers, units of measure, etc.).

It depends on what you're looking for, of course. There are certainly a few unique features that are very nice (e.g. type providers, units of measure, etc.). Compared to Scala, there's much better type inference and more of an emphasis on the functional as opposed to object-oriented side, though both languages support both paradigms (and Scala supports things like higher-kinded types which F# lacks). Compared to other ML-family languages, F# has broader access to libraries thanks to its very nice .NET interoperability (but much weaker support for true ML-style modules). F#'s tooling is also much better than that of most functional languages (especially on Windows via Visual Studio, but people seem very happy with the tooling on Linux with Mono, too). But personally the thing I most like about F# is the community.