I’ve switched to ADSL2+ through my enta reseller, and although I’ve seen speeds around 15000kbps, more often than not I'm only getting speeds similar to my ADSL Max connection – around 5500kbps. Regardless of my actual throughput, I’m generally syncing at about 18000kbps.
Initially, my upload was very slow - below 200kbps at times, but that’s now sorted and it’s over 1000, so things are getting better.
I’ve had no stability issues so far, but my download and transfer rates aren’t what they should be. It’s very early days, and there are certainly some issues to be resolved, much like ADSL Max during its infancy. Some people are very quick to complain about poor speeds, but it was never going to be a smooth transition for everyone. It's worth remembering that ADSL2+ is pretty much just a by-product of BTs new network.