Also, the actual HMD (excluding strap, headphones, cable hooks, etc.) of the Vive is still about 40% heavier than Rift's, so there's still more "face tug" and fatigue over longer sessions.
Again, I have not directly tested this, but it makes sense as there's substantially more plastic in the Rift's strap system (i.e., back of the head) than Vive's.
Edit: It seems the initial Vive release was heavier than the Rift but the latest release is lighter.
The new Vives weigh about 468g. According to Amazon, a replacement back strap weighs 1.8 ounces (51g)[2]. The Vive HMD w/out strap would be - at the least - about 417g.
Even at a 417g weight, that's about 30% heavier than Rift's strapless weight. Since the 1.8g may include packaging, the HMD may weigh a bit more, bringing the % up to 40% or so.
[1] https://www.reddit.com/r/oculus/comments/47rb3m/the_rift_cv1...
[2] http://a.co/6PUVw7v: "Package Dimensions 4.2 x 3.9 x 3.9 inches; 1.8 ounces" (so 1.8 ounces may include packaging).
Tracking is less of a hassle on the vive. Fewer cables, easier.
rift has their own ecosystem which can also play almost every game on the steam library.
vive primarily has steam, but with some hackery (revive), you can play some rift games.
Hardware-wise, they're practically the same. Comfort-wise, Rift takes it.
Development-wise? tough, but I think Rift takes it as well. You get a free license for unity or unreal4 i forget which. And they've improved the developer documentation greatly recently.
The good thing is most multiplayer games support both.