The R10 is the best dynamic headphone I've heard (and I've heard most of the top dynamic headphones). However, as vertigo-1 has indicated, $3600 is in Stax territory. The cost of the Sony is only part of the expense. The R10 demands a truly great amplifier. The EAR HP4 is the best I've heard so far, but that's a not inconsiderable expense in its own right.
The three best headphone systems I've heard are the R10/EAR, Stax Omega II, and Sennheiser Orpheus. I've only heard the latter two once, and can't really do a meaningful comparison.
If you can get a set sent to you from the Orient, you may get tagged with customs fees, which will greatly reduce the apparent savings (the importer is only part of the higher price).
Have you heard the R10? That's really the only way you can make a meaningful value judgement, but it can be difficult finding one you can listen to. I'd think long and hard about paying $3600 for something I hadn't heard, and that I couldn't return if I didn't like it.
I felt comfortable buying used, because 1) what I had read indicated that it would be something I'd love, and 2) there was a safety net, in that if I didn't like it I could probably break even, or only take a small loss if I decided to sell. If you pay $3600, you'd better like it, because I would imagine that $2000 or maybe a little more would be a reasonable resale price.
If $3600 is the only way you can get one, you can afford it, and it's something you know that you'll like...