I've had the Home Surf service for a few months now, and am really pleased with it. I went for the router pack as I'm running my own web and mail servers on an old P100 Linux box as well as using a Windows PC for "home" use.
I run three web sites off the Linux box and operate a "mail forwarding" service for my church, so that members can have consistent mail addresses regardless of their "real" address.
The speed and reliability are both excellent. I have a script set up that tests network connectivity by pinging PlusNet every 10 minutes, and rebooting the router if it's down. Currently I'm seeing about one reboot per day, although in the late summer I went three weeks without any downtime. Some of these reboots may be due to the router.
The only technical problem I've seen is occasional DNS server failures and delays.
I was nervous about going for the cheapest ADSL package when I signed up, but you guys really do seem to be head and shoulders above the rest. Your tech support tends to know what they're talking about, and your basic account contains everything I need - static IP and SMTP mail.