[ditoa]

Yes. IBM, Red Hat, etc. Also there are tens of thousands of users running distros such as Debian on system much bigger than Windows Server can allow. While saying "first party supported" isn't like for like with Windows (if you are running say Debian) it has a proven track record. While Mono is very good it is still very young. Obviously this is personal opinion but if I am in discussions with vendors on what software stack we are using saying Linux isn't going to get me fired as it is pretty much know to the whole IT world, even PHBs, Mono not so much. Reputation matters a lot. Linux has a good rep in the enterprise world.

[profquail]

I agree, Linux does have a good rep in the enterprise world. My point was simply that, by the open-source, distributed nature of Linux/BSD development there isn't a true "first party" that has control over the whole thing. IBM, Oracle, Red Hat, Canonical, et al., certainly do well supporting Linux, but by definition they provide third-party support. (Unless they're providing support for code they've developed and contributed -- that would be first-party support.)

[ditoa]

Agreed, by definition, you are right. However the whole "Linux is free therefore it can't be good" attitude that did exist circa 10 years ago is pretty much dead these days except for some hardcore MS customers who are blind to the real world.