Considering that currently only ORANGE UK have a functioning EDGE NETWORK.
And I use the term functioning loosely (Edge works in most city centres),
but its far from faster.)

The current situation on orange is if GPRS is congested
and falls over and you have an EDGE enable mobile then congrats you have
some slow connectivity as opposed to getting disconnected on GPRS.
ORANGE recently has been voted by users THE WORST mobile company
in the UK. *See various recent newspaper articles*.

It is rumored that O2 might have a functioning Edge Network Up by
December. Please note O2 is the only UK Network not to promote
3G AT ALL. (They seem to have it, I did get a 3g sim card, but
there are virtually ZERO services or promotions for 3g on O2)

Vodafone/Tmobile both have fully functioning 3g networks and should be able to handle
the IPHONE. T-mobile has an acceptable flat rate data tarrif, Vodafone is catching up. O2 is an ok mobile network (but read old school, lacking in investment and new technology), the lack of EDGE and inability to promote 3G would be more or less like AT&T in the usa.

So as you can see there are many surprises in store for is this fall.
We just have to wait and see.

3G Mobile Solutions