BIG YES!
MORESO: you'd have to be a fool to buy a nMP for video editing (or at least someone who hasn't done your homework).
You can build a machine that is much more than a top of the line $9,500+ MP for a fifth as much.
Here's the recipe for a cMP that easily edits 4K in 60hz (I just put this together):
1) $1000
Buy a 2009-2012 Mac Pro with dual processors (any processor spec). 2009's (called 4,1's) can be flashed to 2010-12's (called 5,1's). That said, once you flash a 2009 there are some reports about inconsistent fan stuff so IMO it's better to go with a 2010 or a 2012 [this is somewhat unclear to me--someone please set the record straight on this].
Note: already have a Mac Pro with a single processor? You can buy one with a double and switch the CPU trays and then sell the other unit.
2) $600
Go on Ebay and spend $600 on two matched Hex 3.42 chips:
http://www.ebay.com/itm/Twelve-Core...219251?hash=item4b077d9a73:g:I4QAAOSwKtlWp9Q2
3) $318
64GB Ram from OWC
https://eshop.macsales.com/shop/memory/Mac-Pro-Memory#1333-memory
4) $660
GTX980Ti from Mac Video Cards.
http://www.macvidcards.com/store/p49/Nvidia_GTX_980_Ti_6_GB.html
If you're editing in FCPX then get something for that. But if you're editing in Premiere--or use Adobe stuff at all--then you need a CUDA card and this one is AWESOME. You can put a 980Ti in that isn't flashed for Mac, but you won't have a boot screen (not that big of a deal for most people).
Note: putting in a non-Apple certified video card in your system means you gotta be on your drivers and usually be a slow adopter for new OS updates. It's also a good idea to have a spare Apple Certified video card to put in just in case you forget and update your system to something that isn't compatible yet.
Note2: the specs on this blow away the stale 700's on the new Mac Pro.
5) Drives (depending on your needs)
I like an SSD on a PCI for your system. You'll also need an array of SSDs for your projects, backup drives and so on.
You'll need all this for whatever system you get. If you get a new Mac Pro you're gonna have to buy an external drive bay.
The 4k and 5K videos I edit are all short--around 5 min--so I use a pair of 500GB SSD's on a Sonnet Tempo [which has eSATA connections for backing up to external drives] set in a Raid 0 stripe using SoftRaid. The beautiful thing about a classic Mac Pro is you have TONS of internal storage space. I've got a SSD in my second optical bay, all four HD bays stocked with backup drives, a system disk on a PCI card and the Sonnet Tempo with the Raid.
Total Price: $2600
And this system totally keeps up with the $9500 top of the line Mac. The new Mac has Thunderbolt but who cares: classic Mac Pros have so much space inside for connections AND PCI SLOTS! I have and run everything here and my benchmarks are just a hair under the $9500 Mac Pro. At the end of the day, 12 cores is 12 cores and 3.46 is 3.46. Also heads up: Premiere doesn't even use all 12 cores all the time [so you can imagine the face palming people do who actually spend the big money for this].
If you wanna get fancy you can add a Dell UP3216Q monitor to see your 4K worth at 60hz, I have this this setup and 4K looks STUNNING.
