Been with O2 for 2 years now and only ever had 2 drops and even then only for a few seconds and back on again, never had an outage.
Speeds are consistent and I get approx 5-6Mb slowest was 3Mb for a day.
Don't use the ISP email, can't see the point, its google and hotmail for me. Downside to O2 is they don't do any webspace, not even a token 100Mb, but hey there are plenty of free hosters out there so not such a baddie.
Never had to phone CS because the connection is just great.
Highly recommended.
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