My experience, supported by press comments, is that Vodafone have one of the most extensive and fast 3G data networks in the UK. I certainly have few complaints about not getting a signal and I normally find that it's a fast connection. I've done speed tests and logged up over 2 Mbps, which is pretty good (the modem is rated at an optimistic 7.2 Mbps but I don't think the network yet supports over 3.6 Mbps). Like fixed broadband connections, the speed must vary depending on the traffic load and the number of users in a particular location.
But one thing sucks with the Vodafone for Mac experience. The software is dismal and lacks any semblance of design or user-friendliness. It pops up to activate the modem and then disappears as soon as you activate the service. You have to be pretty slick to jot down the usage to date shown on the opening screen. This is the only way you have of checking what you are doing. Once you have connected, there is no monitoring, nor any way to send text messages. All these problems are addressed by the far superior Windows software. Sadly, this piece of Mac software has not changed in the three years I have been using Vodafone products and is well past its sell-by date.
I was reminded of this again over the weekend when I was asked to set up a friend's T-Mobile pay-as-you-go data card. The T-Mobile software for Mac is excellent and you can monitor your usage very easily. It also allows the sending of SMS messages as you would expect. Incidentally, this deal from T-Mobile costs £2 per day for unlimited downloads (with a 3GB "fair usage" policy), which isn't bad at all. The weekly and monthly PAYG options are less attractive and you are better off with a 12-month or 18-month contract.But for the occasional user, £1.70 a day is great.
My friend will use the modem only occasionally, not more than on three days a month, so this makes sense. My message to Vodafone is to start looking after their Mac customers.