I have tried most of the PAYG dongles and would rate the 3 one for the best coverage, however when outwith a 3g signal it wont connect. I now use the Vodafone dongle as it connects everywhere, its slow on GPRS but at least gets you connected. The other reason I use the Vodafone is that when you top up £15 that lasts until it runs out unlike the others which only last over a 30 day period and dont carry over. I have the internet on all the time while I'm driving so I can listen to internet blues radio stations, for the same £15, 3 gives you 3 gig usage whereas the Vodafone gives you 1 gig but I can easily use up the 3 gig within two weeks but have had the Vodafone last up to six weeks with the same usage as the 3 dongle, which is odd, and thats been tested back to back over the last year
Unfortunately Voodoo dont supply that dongle anymore, they only supply 30 day dongles now.....however you can find the time unlimited ones on ebay....last time i looked they were going for about 50- 60 squid with 1GB preloaded
I got the sim from ebay that gives the unlimited time/till credit runs out, and think it was aboot £3/£4