PCP on a 50% depreciated 5 year old car?

Looking at upgrading my car to one around £25k-£35k and have narrowed down to a few options. All seem to have come well down in the depreciation curve, over 50% from their original value.

All the cars are 5-6 years old with circa 40k miles on the clock. I am able to get shorter term 2 or 3 year PCP deals on these. I imagine that I would be in good positive equity once the term is over as the depreciation has already occurred.

Would there be any reason not to do this? I could also afford to do a hire purchase / bank loan instead.