Digital Quandry - is it reliable?

The likelihood of your camera dying at 4k frames is slim to none, and was probably an isolated problem with a batch of D2x.  My D2hs from the same era has been used as a workhorse since 2005 without a glitch... and has much more than 4k frames on the shutter

Absolutely not.  Medium format is my favorite format but unless you have a particular reason to shoot it, it's mostly a waste of time these days in my opinion.  All the messing around with film, ordering, loading, possibly having to repair the film holder, mailing film for processing or scanning, scanning dust or hair, etc...  what's the point when all of that could've been done with a D800 or 5d3?!

... and if you don't already have medium format lenses, then your purse is in for another kick-in-the-teeth.

I sincerely think if you got a D800e, the 14-24, 24-70, 70-200vr, 85, and 24 f/1.4 lenses you'd be set for pretty much anything you'd want to photograph AND you'd be far more satisfied over investing in a medium format system that I think you'd wind up (no pun) having a sour stomach over after a few weeks.

Get a great dslr with a decent warranty and be sure to insure your gear-  that way whatever happens, (whether it happens at 4k frames or 104k frames) you're not in as much of a bind.

Best of luck with your purchase decision!

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Teila K. Day
http://www.teiladay.com