>That was always my suspicion, and I used to move all string concatenations to LLF when dealing with multiple MB's of export data. It would increase the performance by a factor of several hundred times.

A bit upthread I wrote to JR about the counterintuitive, but clearly measurable benefit of piping into file compared to concats of already long strings.
In my tests (AFAIR already back on 32-bit XP, but would not bet large sums...) Scripiting.FileSystemObject gives you better performance, esp. if strings are long.
As those test were not micro-benchs, but alternatetive implementations on the data we used, so as always, measure your own data ;-))