I've just bought a new bike this way.
Advantages:
save the VAT (16.67% of gross price of bike)
save the corp tax on the net value of chosen bike at your highest rate
Disadvantages
you do need to be a ltd company
to take advantage of the VAT saving you obviously need to be VAT registered
took the 'effective' cost of my bike from down by about £500
Best to check with your accountant first though