Anyone looking for a chassis should take a look at these. I own one with a Tikka action and like it allot, very well built, very configurable, very comfortable to get behind.
My primary gripe regarding the AICS is the palm swell, which is now solved by viper skins - but - I do have a problem with paying $900 for a chassis, only to pay another $200 to make it fit me better. That said, it is a high quality piece of gear.
The Whiskey 3 has a good, generous palm swell (for us with non-girly hands.) It is available in a folding version (mine is fixed, not folding) and takes AI mags. LOP and cheek weld are adjustable, as it fore rail and about everything else.
I have not used the XLR or JP chassis.
Another option is a Manners stock with chassis. I have a T5A with chassis and love it, very comfortable. Also, if you do Manners T5A, call Tom and ask him to use the right-handed version but with a lefty bolt, that is what I did on my 40X and it works great. The rightly palm swell works great for lefty shooting, more comfortable than the ambi setup.