It's important to understand that Thunderbolt provides (external) access to the PCIe bus.  
Nothing more/less
Under ideal circumstances, you can expect performance on-par with PCIe.
 
 
To achieve PCIe level performance, you have to meet all the following conditions:

• Running one of the latest Z170, Z270, or X99 motherboards that provide Thunderbolt-3 via USB-C port
• Running an up-to-date install of Win10
• Need a USB-C to Thunderbolt adapter
• Your audio interface needs full "PCIe via Thunderbolt" driver

 
Currently, only MOTU and UA have "PCIe via Thunderbolt" drivers that are actually available for Windows.
 
For a Mac user, Thunderbolt is critical.
On any current generation Mac, Thunderbolt is the *only* way to access the PCIe bus.
PC users have PCIe slots... so Thunderbolt is much less critical.
 
Thunderbolt is owned by Intel... so it won't be going anywhere anytime soon.

Jim Roseberry
It's important to understand that Thunderbolt provides (external) access to the PCIe bus.  
Nothing more/less

this

I've decided to built a new PC with Thunderbolt. Now just finalizing the details, but here's what I've got so far:
 
Gigabyte GA-Z170x Gaming 7 motherboard
G.Skill F4-3000 2x16GB (32GB total) DDR4 3000
Intel i7-7700k processor
Noctua NH-D15 6 heatpipe with dual fans
Gigabyte GeForce GTX 1070 (I'm a gamer)
EVGA SuperNOVA 750 G2 Power Supply
 
I'm going to consolidate a number of hard drives to a few 1TB SSD drives while I do this. I usually upgrade my existing system in my rack case but I decided to build a new machine from scratch so I can keep the old one going during the process. 
 
I welcome any input on the build...