Just skied the Spitfire's for the first time today on a couple groomer laps. They skied great, I was very impressed with the stiffness (all the power I could ask for, even without the booster strap) comfort out of the box (I'd say they have a narrower fit), and buckle system (very easy to change from uphill to downhill - and no need for a booster tongue like the TLT 5's)
Be aware however, that the actual weight of my size 26's is 1160g, or just over 5lbs per pair. I checked with La Sportiva about this, and they revised the weight on their website. Hopefully Backcountry and other retailers will follow suit!