Just got back from a trip to Cornwall... took my new 3 Dongle with me.... very pleased with the results.
I bought the ZTE dongle for £49 , no contract , PAYG (black one with green stripe not the white one) and topped it up with 1Gig for £10. I did a fair bit of browsing , emailing and downloading of geocaches but still only used about 1/4 of my data allowance in the 9 days away.
St Austell :- good HSDPA (High-Speed Downlink Packet Access ) signal with no problem accessing websites or email. I did a speed test here DL speed appx 380- 500k.
Veryan C&CC club site:- HSDPA signal not as fast as at St Austell and I think I was lucky being at the higher side of the site ( on a hardstanding)
Lizard ( Henry's Campsite) ...no signal at all but then few mobile phones work right down here either...my Orange phone just about managed to work up in the village. ( standing on the table at the pub
Helston :- good HSDPA signal, good speed
Marazion :- HSDPA signal, good speed
Lanhydrock :- ( near Bodmin) HSDPA signal, good speed
Weston Super Mare ( seafront) HSDPA signal, good speed.
The Picture is where we were sited in St Austell...it could explain why the speed was so good
( I am not sure if that mast carried the 3 cell transmitter but we were on high ground and I am sure that if that is not the mast for 3Mobile it was not far away