I changed from 3 to Vodafone on a 30 day sim only deal as the N900 didnt accept 3 sims initially. After being on Voda for 2 months the signal is stronger especially inside and the connection faster (to load web pages) than 3. Its more stable too. I have about another month left on the 3 sim before I can give notice so may try it once more as its internet policy is unlimited (1gb fair usage) compared to the crappy voda 500mb policy.