Since you've been left hanging Toma, I'll give my humble opinion.
I recently bought a 2010 kite which had no repairs and in "great condition", to be honest I think the kite had seen a little more airtime than I had expected but found the fabric to still be quite crispy and was still very happy with the price I paid. I also did not try bargain down the seller and gave him his asking price so I think we both felt like winners.

My advice would be to see both kites before you buy, I think overall condition of the fabric is more important than the odd pinhole patches if they are properly repaired. The kite with newer (crispy) canopy will last you longer. Quite often the pigtails are a good indication of how much action the kite has seen.

All the best with it.

If it's had replaced pigtails, then the old pigtails must have been worn, which is suggestive of the level use rather than the level of care taken.

I would say a pinhole would take a couple of hundred off the price. Not that a pinhole affects performance, but a kite with any damage/repair is more difficult to sell.

Try to find a seller who flys a quiver of kites. I have always had a three kite quiver, I've never replaced pigtails and kite very regularly. I only use one bar/lines however and as a result see fair line wear after just one season of use. I also notice my 8m kite (being the most used) has more wear than my 10m and 6m. But consider if I only had an 8m - the wear would be considerably more due to more flying time and more time using the one kite in under/over powered conditions.