Sorry, 2.5 was me being sarcastic, so I put it in quotes. It basically means you code mostly in C# 2 with a few C# 3 features cherry-picked (Like null coalesce, maybe implicit typing with var) but avoid anything LINQ-related.

"features are too scary and unproven"

Right, because lambdas and closures haven't been around for 40 years. Sigh.

Actually they're right. It's very easy to fuck up in LINQ and end up with code that balloons memory or scales poorly for example.

Not if you know linq.

That's a fairly arrogant statement. You might know LINQ but does the consumer of your IEnumerable<T>? Not all team members are equal.

Most of the problems arise from people not understanding that linq queries return iterators, not collections and therefore writing O(n²) loops. But that's not too hard to learn.

Alas, if you are talking about Linq2Sql or Entity Framework, then of course you have to deal with all the typical ORM problems; but this has nothing to do with Linq.

I think the common sentiment is that we'd all hope to hell that we never have to work on a project so crappy that team members can't understand programming language basics.