I have a 2-3 year old Gazelle and a 2015 mbp. Here's my opinion: the Apple has beautiful hardware, retina screen, and an nvidia gpu. I hate everything else about it (e.g. mac os). The Gazelle shell is just a System76 branded generic laptop, but it has an i7 and ssd. The thing is a powerhouse, and I use it for almost everything.

My advice: if you want a solid development platform, System76 is the way to go (and will cost half as much). If you care more about a nice retina screen and dont mind mac os, stick with a mbp.