I wouldn't use it for super important services.... But, I hear OVH/SoYouStart have decent servers. Their support & uptime are pretty shoddy at the best tho.
All of our machines at Paperspace <a href="https://paperspace.com" rel="nofollow">https://paperspace.com</a> have GPUs and our pricing is much more affordable (disclaimer: I'm one of the founders). Currently only Windows but Linux is coming soon :)
I'll bite. WHY? the crazy spot price? whats wrong with physical hardware? The "cheapest" option is to just buy some graphics cards; but that doesn't scale well. Is that why you need "GPU SERVERS"? Your question is meaningless without some background information. What are you doing, ML? What's your stack? how much memory do you need?