I got my A4000 recapped at Amiwest by Acill and he did a great job. His prices are very reasonable too.
The recapping is a problem that affects a lot of older computers. The caps leak and can do irreparable damage to the motherboard. I would say it's a priority once you get the machine. That way you can enjoy it for many years to come without that nagging worry in the back of your mind.
