As I mentioned in another thread about UTV Clicksilver BB I recently opted to upgrade from 2Mbps to 3Mbps. I've been using 2Mbps since early 2005 and generally it has been OK. A few outages and sporadic random diconnects and I find UTV technical support OK on the phone but they never answer emails and rarely call you back when they promise. Anyway the upgrade to 3Mbps took effect from the start of August. On 2Mbps I was generally connecting at just below that and getting an actual throughput of c. 1.6Mbps. During August I was monitoring the connection and throughput speed and they remained more or less the same. I called UTV (three times - each time they promised to call me back but didn't) and eventually was told that eircom tell them that my line is only 1Mbps capable. I told them that I was getting 2Mbps fine for 2.5 years and they said that I must've been lucky. 
Anyway - one way or another it looks like my line is not 3Mbps capable (I'm c. 2KM from Temple Bar exchange), UTV don't bother checking this when you upgrade and will just charge you for the upgrade whether it works or not. It's up to you to find out that it doesn't, get them to investigate/sort it out and, if necessary, downgrade and get a refund of any payments made for a service not received.
Anyway - one way or another it looks like my line is not 3Mbps capable (I'm c. 2KM from Temple Bar exchange), UTV don't bother checking this when you upgrade and will just charge you for the upgrade whether it works or not. It's up to you to find out that it doesn't, get them to investigate/sort it out and, if necessary, downgrade and get a refund of any payments made for a service not received.