I have an Akitio Node. It's noisy as hell, but fits a full sized GPU and quite hackable - there are some silent fans mods if it bothers you.

There are plenty of gotchas, so make sure you read up on egpu.io and /r/eGPU

But once setup, and when Windows doesn't break everything with an update (happened with the Fall Creators update), works great and performance should be within 90-95% of a desktop setup, provided you're using an external monitor. You can use the internal LCD, but TB2 bandwidth will be the bottleneck in that case, and you'll get a bigger performance hit.

Here's my success post on reddit: https://www.reddit.com/r/eGPU/comments/77e86g/success_macboo...