I would prefer a Linux VPS because I would assume that it would be cheaper since the software is free. I also like Linux there are so many different OS you can choose from for your server and can be quite challenging to set up which is why I like it.
Honestly I would prefer a Windows VPS as though linux VPSes are better made webservers as compared to their Windows Counterpart, yet Windows VPSes allow one to run Windows based apps allowing slightly more versatality than that offered by linux. But then again I am kind of a linux noob anyway so it does not make much of a difference anyway...
Even I'm a beginner, I choosed linux over windows. Even it's not so intuitive as windows and not using graphics on my vps, it's more powerful. I run a vps on 512mb ram and it powers a website with around 2.000 sessions every day. It can handle all the traffic and still has some ram available.
Linux for sure. It's more secure. The more bells and whistles for creating a user-friendly desktop environment the greater the risk for hackers to get in. Command line is always better from a security point of view.
I used windows server and I also used linux servers , my preference goes to linux because in my case I used it for a game server , and as the linux system requires fewer resources on going faster and you could connect even more players servers . I used ubuntu also to make the php sites with apache , and I must say that everything worked perfectly . In general I think it is more efficient as a server linux but we must learn to use the controls .
I would prefer a Linux VPS because I think that it would be cheaper and since linux is opensource, there will be more support. I also like Linux because I think Nginx is easier to setup than IIS on windows.
I prefer Linux since i have problems using new versions of Windows - i only use Linux on all my computers for several years. I remember all the problems i had with Windows in the past and i don't want a part of this any more.
Linux is number one choice of OS for web-servers and mail server - see the ranks.