Your right to think of it as just a way to get an interest free loan on a nice bike.
In reality as everyone has said you dont really save that much. i think i will save just under £200, still better in my pocket.
You should get the option to lease the bike for a further 3 years at a cost of about £80 in total, after that its yours to keep.
Be aware that they DO NOT have to sell it back to you but in reality they will.
Go for it get yourself some decent wheels.
I bought my first MTB this way in May and i probably would not have bought such an expensive bike if i was paying cash.