I ran speed test each time I successfully connected to the bluetooth ...that was the first thing I did. Like you, I didn't want to waste my time if the connection was slow...It tested out to the same speeds as my USB tether was testing to...or at least close?..I think it was like 700kb download...I can live with that!
I should say, where I use it mainly is only 3g..do these numbers sound right to you, because I was surprised at how fast the connect was!