I did migrate from Seriously Internet, whom I was pretty happy with, but like yourself wanted a faster connection!
After I got my MAC Code from Seriously which took a couple of days, I placed the order with Be on the 23/11. Next day my order was accepted with a planned activation of 4/12. My BeBox modem was sent 30/11 and received on 4/12. On this day my Seriously connection stopped working...
Sadly, the MAC code provided wasn't recognised by BT or something so after a couple of days messing around in my exchange, it finally got activated on 8/12! Super quick as well...
Was a bit annoyed on Christmas day as something went wrong in the exchange and this lasted until the Wednesday after Boxing day but it was sorted that day! Thankfully I was out socialising so didn't really miss it.
Apart from that, its been great. Request your MAC code from Nildram!!!