Thank you very much all for your answers.
To sum up: small prices = bad support?
I will try all VPS I guess. IMHO, in the thread dedicated to VPS (
https://bitcointalk.org/index.php?topic=39251.0) , it would be good to do 2 sections, one for cheap and light vps (cinfu, bitvps) and one for the others.
After bitvps and the erratic support, I guess that my next move will be cinfu. I will see if my reverse dns request will be faster lol.
I read that bitvps has just changed all their team. This may be the explanation (or maybe I am fully naive and all cheap vps have a bad support
)