There is absolutely nothing to choose from between Cameron and Brown. The Tories and Labour are so close in tone and ideas that it's actually pretty hilarious watching members of the parties try to debate as half of their arguing is over semantics rather than policy, since Labour stole half the Tories' policies to become electable back in 1997 and lost a large chunk of their traditional left-leaning support base in the process.

In fact, replacing Brown with Cameron as PM will almost certainly result in less of a change of policy and attitude then replacing Blair with Brown did.