nothing wrong with buying anything from eBay. I have purchased two laptops that worked for over a year, the price I paid made it viable for them to only last a year. I have purchased a faulty one repaired it and sold it for double.
You are protected with PayPal for up to 45 days, however if you file a dispute on day 44 you get a further 20 days to escalate giving you 64 days protection, however it is knowing if it is going to go wrong or not on day 44.
Plus if you pay via a debit card displaying the VISA logo, or even a credit card you get 90 days protection as you can initiate a chargeback. Not all cards allow it though but they generally do.
However, if you want a years guarantee buy from the high street.