Just thought I'd add my tuppence worth
Most of my Volvos have been autos - by the nature of Volvos they've been high mileage, all over 100k. I decided to change the ATF on a 960 as the gear changes were getting a bit sluggish and the overall performance was dropping. I looked into the various alternatives and did some reading of the Brickboard - the Volvo Owners Forum of our American friends. After getting resounding positive feedback about Amsoil I bought some from the US and had it shipped over... It wasn't cheap!
The transformation was instant and obvious - it was more responsive, powerful and the economy was improved. To be honest, it had perhaps 160k miles up and I'm not sure whether it had ever been changed, so simply having fresh ATF would have improved matters, but every since I've only used Amsoil. Can't recommend it highly enough.
I know this sounds like a sponsored advert, but I assure you I'm just a happy customer
