I'm perplexed.... Having had a really bad time with an O2 PAYG SIM with E160 dongle recently (disconnecting every few minutes, admittedly in a mostly EDGE area), I did a couple of tests with Vodafone from exactly the same window at home, with dramatically different results:
1. iPhone 3GS with contract Vodafone SIM - speedtest.net on iPhone gave 4.6 Mbps down, 0.3 Mbps up, 200 ms ping, with 2 to 3 bars of 3G signal showing on phone.
2. Huawei E160 dongle with PAYG Vodafone SIM - speedtest.net on Firefox gave 0.03 Mbps down, 0.02 Mbps up, and 870 ms ping. Can't check signal or 3G/EDGE, but it must have been EDGE if not GPRS.
Curious to know why the massive difference here... Perhaps the E160 is not so good at holding onto 3G signal in low-signal areas, since the iPhone has a better antenna?
I also have a Huawei K3765 dongle in case that would be better.
The E160 was originally from O2 but was provided unlocked. I have had better speeds (at least 100 Kbps) with the E160 using an O2 SIM from the same window.