Depends on the person in how long it takes to transfer - and getting used to flying different aircraft will enable you to become more of a pilot and less of an operator of a single type of machine.
I'm in the middle of my PPL and I'm now on my third type of plane. I've probably spent (I could say wasted but I don't think its a waste of time) around 3 hours total moving from one to the other - and I was landing each one straight away. But it does also depend on how you've been taught. I've been taught in a generic non-plane specific way, with a number of key mnemonics rather than plane specific checklists. I just skip out setting the variable pitch prop when I'm in a PA28...
If you have the opportunity to try different types - I say go for it.