Sorry for the delayed reply but...
No, handing it back at the end of the agreement won't affect your credit rating - the whole idea is that this is an option when you start the finance agreement. You'll very rarely get positive equity at the end of a PCP these days as the "bubble has burst" somewhat
Some companies view it dimly if you utilise the option of what's known as "halves and thirds" whereby you can voluntarily terminate or VT you agreement once you've paid back over half of the total amount borrowed - it's a clause in the T&C's not many people know about but it's a potential get out early thing.
New is often as cheap as 3-5 years old with PCP as there are manufacturer supported deals to be had - most manufacturers have deposit contributions on certain models and the total margin they could potentially use to do a deal is around 15% - some models even more than that. Go to a dealer at the end of the month / quarter and know what you want to acheive. Don't use the "well you tell me your best price" and keeping your cards close to your chest thing just makes the whole process more laborious - make a salesman's job easy by telling him where you need to be for a deal and they'll do their best to get it for you. A card ready to place a deposit gets things done!
...the voice of 10+ years experience in the trade
@golgol PCH is a bit of a tricky one, if you know you'll 100% want the same car for the full term then they can be a good option but if you needed to change the car for whatever reason you'd be liable for 50% of the remaining rentals - plus companies can be super strict on any damage at the hand back stage