I think there are 4 different types of prospects;
the miser - this person doesn't care about anything but getting the cheapest hosting they can get, mainly because they might just use the host for random projects that don't have a long-term goal and it's simply a hobby for them, this person...
Fair enough, but there's a bigger chance of things going wrong on a Windows server, there's a reason Linux is more popular. Plus Linux offers more security and it's open source, with Windows you're at the mercy of Microsoft.
Reliability and uptime - less than 99% uptime is problematic now a days
Customer support - 1 hour response time would be ideal
Unique features - what makes them stand out from the thousand other reseller hosts?
Price and value - are the prices competitive?
Scalability for future growth - how...
What? This sounds like nonsense lol
Windows uses a great amount of more resources than Linux, so no, it's not more stable than Linux, at least in terms of hosting.