Just from my experience, .NET as a platform for startsups can be made to sound really good by the people selling it, and there are some startups out there doing it and making it work for them, to which I say good on ya! But from my experience, it ends up being the boat anchor weighing you down. There are a TON of developers available, but finding good ones can be very difficult. Hosting is expensive (compared to linux-compatible solutions), and third party components are plentiful and expensive, and usually still require a fair amount of work to integrate.
My boss at my last job used to say "how can we make this faster? Why is everything so slow?" Well, because you started with a code base written by people who aren't really passionate about software development, they just took your specs and spit something out, so it gets the job done, but just barely. Then you bolted on a bunch of fancy UI components and ajaxified some stuff to give it the appearance of being less slow (oh, and look how pretty your GumDropGridView is!) Cram all of that into the cluster (f*ck) of servers in your server closet and you had a webapp you could start charging people to use. Now you've hired me and you want me to tell you how to make it faster? Well, it can be done, but we've got a lot of work to do. What's that? You've got 3 months worth of funding left? Dude, what do you want me to say?
Does anyone have proof of this?
My personal observation is that most companies will still be around and they'll neither be millionaires nor broke. In such a situation, the bizspark bait-n-switch can be significant.
Picking technology today on the basis that you'll either crash and burn or be hugely successful in 3 years seems like the sales pitch of a man who lends you free software for 3 years.
That's funny, because I know at least 2 businesses that started out as hacking hobbies ... Apple and Google.
You also don't know when your business will reach the "tipping point", going from barely profitable to hugely profitable ... it could be 3 years from now, it could be 7.
... and until then spending thousands of dollars on software for a single server is just plain stupid from a business perspective, when you could be investing in something else or just give those money away as bonuses if you've got nothing else to do with it.
Like offering free crack to drug addicts! No wonder .NET continues to exist.
SQL Server + Windows licensing can get crazy expensive. I know stackoverflow made it work via http://www.microsoft.com/bizspark/ but I believe even with that program you'll have to cough up the exorbitant licensing fees eventually.
more here: http://blog.stackoverflow.com/2009/03/stack-overflow-and-biz...
You could use MySQL, PostgreSQL, SQLite etc. just as easily.
People are used to throw such examples in the air, like you forgot "hey, there's Mono if you want Linux" ... but how many real apps used by actual people diverge from the MS stack?
Hint: it's not ignorance.
I've designed ASP.Net apps that have had back ends of various forms (everything from navigational databases to Oracle OLAP systems) and once you get over the need to have direct support in Visual Studio then it's not really that big a deal.
YMMV.
A couple of complex queries not optimized at all where slow in MySql and very fast in SQL Server but I think that that is because of the database engine itself and not because of the driver.
I find that the oss/linux/socialist camp has some excellent tools available. But maybe you mean something different by "tools" than I do.
Doubly so if you plump for ReSharper.
There's plenty of great FOSS stuff. I didn't intend for my message to suggest otherwise.