[corresation]

If you really cared about performance you wouldn't use C#, you'd use C or C++

This, in a nutshell, is your argument. And it's an incredibly poor, out of place argument that is founded on ignorance, and does absolutely no service to .NET.

Performance in most modern applications is achieved through proper algorithms and data structures. LINQ is often a hasty short-cut around those, but it offers the illusion of elegance such that many people (such as, apparently, you. It's all functional-like and such, so it has to be good, right?), are blissfully unaware.

Again, a lot of the time that's perfectly fine and causes no real harm -- similar to the way regular expressions might be a costly but powerful catch all -- but in other cases it is not good. That is the case with large scale financial software. If you have a different experience, good for, but simply saying "incredible!" over and over again does absolutely nothing to make your case.

[platz]

Taking a line out of DHH's playbook, perhaps it would be better to discuss a concrete code sample. E.g https://news.ycombinator.com/item?id=7335211