Be cautious when buying refurbs, and of guarantees on eBay generally. eBay defines several classes of refurbs, from manufacturer refurbished to seller refurbished. Seller refurbs may be nothing more than a clean and polish. Manufacturer refurbished are probably the safest, but look carefully at the guarantee.
Don't forget that eBay won't get involved after 30 days, whatever the problem. I bought a manufacturer refurbished petrol mower last year. They hadn't drained the crankcase oil, so after being transported upside down everything was saturated with oil. Otherwise, it works okay, but the engine is a bit erratic and I find myself wondering whether this is why the original buyer rejected it. It only came with a three month guarantee, so after three months of constant rain it had run out after I'd only usedit once! I don't think I would buy a refurb again.