I have been using blackvpn for almost 3 months and I absolutely recommend the service. The speed is not bad when using PPTP but I usually get low bitrates with OpenVPN.
Both security and privacy are great and they claim that they will always be.
I have never used the user support so I can't say.
The price is great in my opinion.
To sum up: I'm very happy with the service. The speed could be improved sometimes (specially when using OpenVPN) but I recommend it.