There is actually a catch (besides very little customer service, which is par for the course with cloud stuff anyway), but it's not really their fault. Hetzner doesn't peer with a lot of bigger players, and therefore its datacenters can have really lousy / inconsistent bandwidth and latency for people outside a relatively small area in Europe (and can occasionally have bizarre outages that are presumably related to partitions). If that's not a dealbreaker for you, then they're one of the best deals out there if you don't want to manage your own hardware and don't need really efficient access to other cloud services like S3 (which obviously work much better within Amazon's datacenters).