I have become a fan of the carrier known as 3 (Three) in the UK.
Why? Because what they sell works.
Because they are easy to deal with.
Because the get the idea of no hurdles. No painful process and no hassles.
I have 5 SIMs from Three between my Nokia N95, the three SkypePhone and SkypePhone2s we now use, plus one in the Mobile Broadband card. With three people working in London last week, the SkypePhones were a blessing at staying in touch with one another and with people we deal with around the globe.
What's more I also use a T-Mobile SIM on my Nokia E71, I found that TMO in the UK is not far behind 3 in how I feel about being a prepaid customer in the UK with either carrier. I'm a pretty happy camper, but it's the simple and easy 3 plans that I like the most.
What I like about 3 though is their integration of devices, and a non-biased approach to working with both Macs and PCs. I picked up a pay as you go 3 Mobile Broadband card. It worked right out of the box and for 15 pounds a month for 5 gigs of data, pretty much all I needed while I was not in my apartment or hotel. The new SkypePhone2 also has connectivity to both Macs and Windows, or by Bluetooth. The update yesterday to the PC software for the Mobile Broadband card that 3 sells was painless and efficient.
Bottom line, if you're heading to the UK or any country 3 serves, you can expect this kind of a great experience. That makes 3 a Working Anywhere Approved carrier.