I've done 4 professional rails apps and many personal ones. I've never had a problem keeping them running. Did you spend any time trying to figure out why they were crashing?
My guess would be that if you've never had trouble keeping things running either they're not real complicated or you don't have a lot of users. And that statement applies to any technology/platform. If you build things long and big enough, you'll fight the technology at points.
That said, even if you have a ton more professional experience than your response suggests, I don't trust people who say never glibly, nor does your question seem genuine.
You're implying the guy's a newb and it's him not the technology--just say as much.
If I were comparing asp.net to something I would consider django or just PHP. PHP has a heck of a deployment story. I run MANY wordpress blogs on the side and centos/mysql/apache/php is rock solid AND fast.
My 2 cents.