Virgin varies greatly from area to area and if a gamer then jitter/latency is generally worse than the likes of Sky/Be
The modem - superhub, if you run it in its modem mode and use your own router is sufficient, but a lot of peoples problems are possibly linked to that device not being the best gateway
Customer Service - fairly standard from what I've seen people post, i.e. nothing special
On the VM 30Meg service, do read their FUP/AUP for the trigger levels at which they slow down upload and downloads.