F# is an awesome language. I'd choose to write F# code any day over any language if my work allows it. The way you are able to concisely and cleanly write code with it is what brought me over. Sure there is an initial overhead (if you we are an OO programmer) in learning all the functional constructs but in the end its all worth it. Even though you might not be able to use it at work (read : management only wants C#/VB.NET), the way you are writing OO code will definitely be improved. I for example have come to appreciate Generics and delegates more because of F#.

Microsoft Research has done such a great job with it and I'm quite sure they will continue to do so.

There is no question that "F# as a language" is great. People do however have a gripe about "F# as a Microsoft product". It is not open source nor is it standard like C#. There is a technology-lockin which I presume some fear will later on will translate into a vendor-lockin.

F# targets mainly the research and financial institutions. I can not say much about financial companies but research instituions and technology companies are big Linux users. There is very high likelihood that these people are also open-source advocates. It will be in their best interest to ensure that the language works perfectly on both Windows and non-windows systems. This is both a win for the users and for Microsoft. It would also propel the language forward at a much quicker pace.

It might be too early to ask this given that the F# CTP was only recently released, but should Microsoft open source F# and get the community involved?