My company paid and I went to a partial NT4 one when 2K had just come out (maybe 3-4mo's out). It was a 5day class and was for NT Server (2) & Workstation (1) tests. The class was very good and I felt confident I could pass the exams but I didn't feel like shelling out the $$$ at the time... for many reasons, including:
1) Didn't directly impact my job
2) Company didn't offer any incentive
3) MS was planning to make NT4 cert obsolete soon, so I'd need new certification... go to #1.
In retrospect, I probably should have taken 'em just for the resume padding, but, fortunately I haven't lost my job and still don't need it. If I do get laid off/fired/etc I can probably spend about a week or so bucking up and take the tests, although they are supposedly much harder than the NT4 ones. Something about complete the blank instead of multiple choice.
Anyway, the class was very informative and was geared towards testing (had Q&A for each section).