Definetely sounds like evildicator knows his stuff, not questioning that. BUT I do agree with Joe Duffy as well with the overuse of split normally for massive dynamic strings and almost always with a collection of strings.. Lots of .NET devs, including myself, are very poor optimized programmers as Joe hints at..
Regardless I also know that Joe and his team is probably working on Midori and the SingularityOS project, that several millions of lines of managed code on a managed os.
Anyway I found some stats of Singularity, of how it improves across the board on certain OS system cycles ... Some of you may find it interesting :