I've been using the Profesional (IE only version) POP3 version at work and the Advanced POP3 system at home for about 1 month now. Althought at first the beta vesions were far too slow, now both systems are excellent. In fact, they're so good that I haven't used my Outlook client for about 2 weeks.
I disagree with jemcom, the web interface is far superior to Outlook. It gives a much better sense of space and the colours are very easy on the eye, completely unlike Outlook's drab grey tones.
Personally I would have not bothered with the Advanced version and concentrated on an even better Profesional version that could be used with browsers that conform to W3C standards (i.e. Mozilla and Opera, not IE), but that's just my view.
All in all a very well designed set of products and one that makes me feel that the web is really coming of age. Congratualtions Plusnet!
[Moderator's note (by Chris P.): Title edited in accordance with link:webmail instructions]