Best Mac pro for the buck?

Hello FCPX editors & Mac Pro owners

My name is Gary and I'm getting ready to purchase a new/used Mac Pro. Within my budget my best options seem to be purchase an older (Big box) beefed up Mac pro or the newer small round Mac Pro.

Below is an example of what I can get in my price range between the two, with most all of the specifics.

I really would like some FCPX editors/ Mac pro owners advice on which system is best and why before I buy.

Short and simple advice would be great. Yes I will be editing in FCPX and doing a fair amount of video compression, along with some high-end graphics.

The big box with typical spec choices in my $ range
Apple Mac Pro 2.93GHz 12-Core 32GB/512GB SSD/2x2TB HDD/Radeon HD 7950 3GB 2009 - Mint

VS

The small round Mac choice
Apple Mac Pro (December, 2013) (Latest Model) 3.5GHz 6-Core 512GB SSD Dual D300

Thnxs!
GB

I would get a refurb now that they seem to have it, if you're on a lower budget. 6-core is nice, 8 would be better, but if I had the choice I would get D700 before upgrading to 8 core. You can upgrade RAM later, but if you're spending this amount I would go for 32 GB. Also, I would rather go D700 and live with 256 SSD if you had to make a choice.

That 2009 is getting long in the tooth, and you won't have Thunderbolt. Not a bad machine, though.

1TB SSD system drive
D700
8 Core
16 GB RAM will work for most projects just fine. I rarely see a project that would benefit from more on my studio's systems.

The main issue will the the media drive you connect. Pegasus T2 is expensive, but the fastest. USB 3 will work really well, depending on what codecs you're editing natively.

No single answer universally. Depends on what your editing and what your future aspirations are over the next 6-7 years, before you an upgrade again.

For editing you will be fine with standard new Mac Pro.
Unless you are into heavy Visual Effects. Yes the bottle neck will be the external drive... unless you Thunderbolt it.

I agree with Ben B. What is your future aspirations? If you know your going to be doing 4K RAW and beyond then build for that.
Just an FYI, I recently built a machine similar to that older Mac Pro. It can handle 4K but it isn't as fluid as a modern day Intel chipset(like a new Mac Pro, iMac, etc...).