I'm interested in exploring VR dev, but am waiting until I have a new GPU, and can't really justify the upgrade yet. I've had my eye on the recent Ryzen cards, but I'm not sold on the reliability yet compared to Nvidia.
I do like that AMD at least seems to be trying to play nice with the open source drivers and kernel infrastructure, but in practice Nvidia still seems to be the most straightforward solution, so... meh.
Don't wait. Iron out the gameplay with "low" graphics. 970 is just fine for that.
I've also run VR games using Windows Mixed Reality headsets, which have a higher resolution than the 1st generation HTC Vive, and it also seemed just fine. Also, at the time, though it was several months back, the Steam VR test program still gave my GTX 970 a pass.
YouTuber Blunty once ran his 1st gen VR headset off of a GTX1050Ti laptop and said it was just fine "in a pinch." (I wouldn't recommend it for the very VR sickness prone, however.)
But maybe after getting some VR development under one's belt with a 970, that may give incentive to do the GPU upgrade if things progress accordingly.