Been running a handful of dedicated boxes on Hetzner for about 5 years now. Even with the increase, the price/performance ratio is still way better than anything comparable from the big three US clouds. Their AX-series auction servers especially.
What concerns me more than the price hike itself is the trend. Memory prices spiking, hard drives selling out, and now this. If you're running anything with serious storage or RAM needs, it's worth locking in what you can now. I grabbed an extra auction server last month just because the specs were good and I figured prices were only going up.
For anyone panicking about alternatives: OVH and Netcup are decent in Europe but have their own tradeoffs. OVH's network has been flaky for me, and Netcup's support is basically nonexistent. Hetzner's support has been solid every time I've needed it, which is worth something.