Services like Contabo are over-selled and resources are highly shared. It's probably better to have 3 vCPU from DigitalOcean instead of 6 vCPU from other cheap services, because in the end the performance will be better. I've had some experience with cheap servers and it's really not worth it, they try to convince you with numbers but it doesn't make sense if you don't get the performance. Sometimes a 1 vCPU VPS from DigitalOcean is going to outperform 2 vCPU from other providers, and you can be sure they use the best hardware and that they care about sharing the resources as little as possible.
To add do this: I've had a very good experience with Hetzner Cloud personally. It costs a bit less that DigitalOcean and performance is comparable (better on some aspects like I/O). Their dedicated servers might be worth taking a look as well.
