I had my 682e wood stock fitted with an Isis and it is very good but personally I prefer the Danuser on my Zoli by a small margin, it seems to absorb more recoil quite simply. The Isis does look neater but to me that is irrelevant as a butchered stock is a butchered stock.
I also had a Gracoil fitted to a custom Teknys but that was not in the league of the other two. The PFS is MoFo best of all in recoil reduction/adjustability/cheek management etc (because the gun free-recoils beneath your face) but the grip shape is unforgiving. It either fits or doesn't and the metal work running through it means you can't necessarily improve things by custom woodwork such as available in the states.
If it were me I would order a stage 2 SofTouch from the USA and be done. These work on the same principle as the PFS in that they allow a gun fitted with an adjustable comb to free-recoil whilst the comb bit stays in place. If your gun is standard at present, then get it fitted with an adjustable comb at the same time. It's often assumed that reducers work by dissipating force away from the shoulder but that is not enough. If you watch really sloooooow motion films of machine gun fire you'll notice the barrel warp and bend under stress, watch slow motion footage of a shooters head and you'll notice some pretty violent shaking exerted to the head, like being gentle punched 200 times on a Sunday morning
. This is fatigue that most people aren't even aware exists.
The SofTouch is pneumatically adjustable I believe and all the reading I've done on the internet seems to suggest that personal preferences and oddities aside, they are the business. I would also fit the comb with a 3 or 5mm sheet of Sorbothane cover (most of mine including the PFS have these), once you get used to the firing cycle and comfort you'll wish you had protected yourself much sooner.
You can borrow my 682e stock if you can get hold of an action and of course shoot the Zoli when I get it back.