if we can, lets please assume we know c# as well as golang (and other languages will not be considered). thanks
That's too bad, as I'd recommend Java and/or the raft of excellent languages available on the JVM.
With C# you're effectively locking yourselves into Windows, which seems a terrible decision from both a cost and scalability standpoint.
With golang you're losing the vast array of open source packages available for the JVM, as well as locking yourselves into a single language which may or may not fit your future needs well.
Scala in particular is an interesting JVM language. Clojure and many others are worth a look as well.
Haven't you read the news recently? C# MVC6 (ASP.NET 5) which is to be released in couple of months is running on Mono and Roslyn is already used by Mono.
C# runs perfectly fine on Linux and Mac.
About the Windows only thing, though: The mono project is excellent for compiling and running C#/.NET on other OSes. We use it on CentOS without much trouble.
Also, the JVM beats the CLR for most benchmarks I've seen, especially real-world benchmarks. Perhaps with Microsoft open-sourcing the CLR runtime, Mono is as competitive under Linux now. That said, the JVM has scaled onto massive systems - I'm skeptical that Mono has similar capability.
Hasn't seemed to have hurt Stack Overflow.
Also, in the end, you will likely change your structure more than once from the first MVP, so I would just make a decision and move forward fast.
As for my opinion. C# is still primarily a Windows environment solution (although its getting better), Golang is a little bit more agnostic but I wouldn't use it anywhere but in a linux environment. My choice would be golang if those were my only two options, mostly because I feel the ecosystem, scaling and cost is better not to be in the Microsoft environment for a startup. However, if you are planning for a Windows based environment, then nothing beats C# IMO.
There are completely valid options that are neither of these languages, nodejs, python or some JVM based languages. I generally avoid the JVM, but that is a personal preference based on my experiences and I recognize plenty of amazing systems are built on JVM based languages all the time.
we have some cost efficient way to get license on Microsoft's software like Windows/SQL Server so the cost on software is not an issue, so is there any other concern with Windows-based solution? you mentioned scalability, why this can be an concern? (I assume windows should be able to do whatever linux is able to provide?)
My comment on scalability and Windows is mostly based upon cost as well as most distributed software solutions that are designed to scale are primarily done not on Windows Server but on Linux of some flavor. I am also biased here as I started my career in Unix, although I spent ~8 years doing primarily Microsoft development, and am dedicated to non-microsoft environments now. In some cases when clients have demanded we deploy on Windows some of the software vendors would tell us to significantly increase the number of nodes when running on Microsoft as they found their failure rates were higher, not to mention less resource efficient. Hence cost goes up more and maintenance increases as well. And no, I wouldn't necessarily say Windows is as capable as Linux, but that may just be some bias sneaking in.
IMO, Java and the JVM haven't kept up with the pace of change in managed languages/environments. Frankly when .NET was released it was worse than Java and the JVM by far but that is one place Microsoft didn't miss the train and they really turned .NET into a power house. Not saying .NET is perfect, but performance issues, predictability, overhead etc all seem superior to me over the JVM. So in general I avoid writing my own code based upon a JVM centered language as I just don't feel it is nearly as resource efficient or stable. I'll say that the JVM is quite tunable to help mitigate a lot of my complaints but the complexity to do it right exceeds the benefits to me when other languages can do what I want without that extra step needed.
I will say though, that I rely on products that are JVM based and I am open to learning some of the newer languages that also depend on the JVM.
FWIW as well, my core language is C++, has been for my entire career. I still use C/C++ but most code I write is node.js with some growing golang mixed in replacing some of the C++ components we have.
I would say it depends what you are trying to achieve.
If it is a regular old web application then .NET will shine, giving you the MVC5 framework which is similar to rails, excellent database mapping, a well integrated web server, authentication and other web concerns out of the box, integration of odata. Let alone the strong typing and excellent generics which is probably the best of the C++esque languages (but its no Hindley Milner but that isn't of much practical importance for a startup).
Maybe use GO if you need it to run cross platform, need to do some insane performance tuning or heavy systems programming. I.e. you are starting a digital ocean or something like that.
Running .NET on linux is possible but may be more limiting. So you are probably running on Windows and the server costs could be higher BUT more than paid off by saved developer costs.
Of course you are also free to use both GO and .NET, using GO where it shines and .NET for the rest of the more prosaic businessey stuff.
On hiring - you will find more .NET devs for sure. Also .NET has been around a lot longer, C# is always getting great new features and there is the excellent F# if you need to do functional programming.
Your biggest consideration as a startup is rapid development and time to market. .NET will get you there faster. Click a button and you have a boostrap-designed, authentication enabled application with a DB back end in a few seconds that you can easily extend. You can get an MVP out in a few hours in .NET.
Without knowing more about your application, I would say it is 99% likely .NET would be a better choice.
https://www.microsoft.com/bizspark/
OTOH Azure is (was?) one of the most expensive providers, so after you outgrow BizSpark it might not make financial sense any more (though if you have paying customers, it will probably not be a significant expense :) and they're betting on it I guess).
I never considered another choice because I come from Microsoft shops (I tried Groovy/Grails and other stuff, but didn't find a reason to switch). I'm extremely happy with my choice so far, I love the IDE and the ease of use, I'm very comfortable with MSSQL, etc...
