Experience with sail repair?
A dock mate of mine (P31) used this service, the head sail was bright white when it came back and "felt" nearly new so we decided the proof was in the puding, we bent the genoa on the boat and went for a sail. Sadly, the sail still blown out, that is to say that the draft was in the same place as before, at the aft end of the sail, not near the luff as it would be with a new sail.
Sailcloth can be made to look and feel new but you basically have the old sail! Is it cheaper than a new sail, absolutely, is it a substitute, NFW. If your goal is to look good, by all means go for it, if you want performance, buy a new sail. Cloth that has seen normal wear and tear of 10-15 years should be replaced IMHO.