2" Rack, as much as I love 1UP (and I do), after losing 5-6k of bikes/tools/skateboards, I wanted the most secure bike rack I could get/afford. That wound up being a Thule T2 Pro XT 1.25" 2-bike rack. (You know me and deals, I got it for free from Performance Bike after I mathed the fuck out of them.) That was my 2nd choice, behind Kuat and just above 1UP, because the built-in security was the best.
Cost no object? Kuat Piston Pro X
There's a Thule T2 Pro XTR now that supersedes mine, and a more rational choice, but don't overlook the in-between Kuat Pisto Pro.
https://www.outdoorgearlab.com/topics/biking/best-bike-rack
Outdoor Gear Lab is a great review site, and a good starting point (trusted by both me and the Ginger Avenger) for most things outdoorsy.
If you have your own system of securing the bikes on a rack? 1UP HD still has tons going for it.