Dave, I waited to reply because I am like Jason in that I don't have my Kalais yet, Matthew is sewing it up as I write. If I remember correctly you have been through both the McHale process and own an HMG Porter so I am equally interested in why you are now looking at one of these two packs and maybe you will give us your details too.
I think like my earlier thread asking for some feed back, which got a few replies, the issue with the Kalais is that according to Matthew there are barely over 100 of them out there, so not a lot of collective experience yet.
My own personal needs are maybe a bit different than most in that I either go out in the fall and winter in the Southeast so need some more volume for colder conditions or I am doing longer trips in the desert and need water load carrying capability (35 # plus). I also need more durability for the harsher desert conditions or the occasional bushwack in the forests of the east (having both torn ripstop packs on thorns and worn holes in every mesh side pocket I own).
Most recently I have used a Mountainsmith Auspex with a great frame/suspension that can carry loads very well, a SMD Starlite and Swift '10 with the sewn own hip belt. After many trips I wanted a combo of the three. I contacted Ron Moak and said I liked the suspension (stays, pad pocket and wrap around hipbelt of the Starlite, the volume of the Swift and the DriGlide back panel of both but would like the Dyneema pockets of their Feather pack. He replied they didn't do custom work.
I looked at the HMG Windrider SW but didn't want a white pack and didn't like the lower compression strap going over the side pockets but liked the look of the suspension.
I looked at the ULA Circuit/Ohm but didn't think it would carry the loads I needed it to, don't like the zig zag side compression but did like the pocket materials and hip belt.
I looked at the Gorilla and liked the material and pockets but wasn't sure about the compression, top pocket or the frame length.
I considered the Borah Stealth as it had the material and pockets I liked but not the suspension.
I thought about the Zpacks Arc Blast but was not keen on the material, hip belt and the suspension seems to be still evolving.
I was just about to contact Zimmerbuilt but was not sure I could get him to sew exactly what I wanted when I read Will Reitveld's review and looked closer at the Kalais. It turned out, with some custom upgrades, that Matthew had put together all the features I wanted: Dyneema X grid material especially in the side pockets, an excellent wrap around hipbelt, a removeable and longer aluminium stay (26.5" long), well designed load lifters (working with the longer stay), spacer mesh back panel, a real internal sleeping pad pocket, well designed compression and back pocket, a well done roll top and a volume that I need (maybe just a bit too much but with good compression...), all at 32 oz. or so.
So we will see, I will let you know after it arrives and I test it out some.
This is the pack he is making for me