You can get cable and you've been using 3G and DSL?
Cable is fibre to the cabinet and then the signal is amplified over the local loop/co-axial runs to the houses, so all the houses can get e.g. 10Mbps on a 10Mbps connection, 50Mbps on a 50Mbps connection and so on.
In theory anyway. Contention knocks that down a bit. From memory the 10meg service averages about 8.9 meg and the 50meg averages 46meg in real world speed tests.
BT's FTTC service is similar, but with phone lines of varying qualities not co-ax, and no amplification, so by definition it rarely achieves the top headline speed and so starts at 5Mbps; you "get what you're given" as with anything DSL based.
Contention is at the exchange rather than the local node, so in theory it should be more manageable and controllable. In theory.
So you could wait for BT's FTTC - assuming your cabinet gets done - and get something between 5 and 40meg, or just have 50meg (if that's what you want) right now.