I’ve just popped into my local 3 store to bore them all about Mobile Broadband (It’s ok, they looked bored already) and I spotted a leaflet that says you get their Mobile Broadband for half price if you’re already a 3 customer. So you could get their cheapest package Broadband Lite for £5 per month. That’s next to nothing!
So if you’re already a 3 customer you should seriously consider getting Mobile Broadband from 3, particularly if you just want to test the water for the first year.
I also found out that their new USB stick modem has got built in Mac installation software which should make it very easy to install. One trick that I think they’re missing is that the sticks don’t have any memory storage built in like a USB memory stick, but I suppose that would make them more expensive and bulkier.