I've had a few days skiing in the Atomic Backland Boots now, so here are a few thoughts. Navigating the baffling range of available ski kit gets harder every year, so hopefully this might help.
I bought the Backland (dangerously close to K2's "Backside"!) to replace Dynafit TLT 6, which had replaced Dyna TLT 5s - I liked the TLT as it was lightweight, skied well, walked well and was OK for ice climbing. The 6 was better than the 5 but the new TLT 7 has changed a lot, going too far down the lightweight route for me - it has lost the toe lug for ice climbing crampons, and doesn't have a removeable tongue. Probably a great boot, but not versatile.
The Backland looks like a good option then, being light, stiff and comfy (more about that in a bit) It's not worth being obsessive about weight, but if you want to do big days touring then you can easily save a kilo per foot without going to extremes - and that will make a difference on a long day! Modern ski kit seems to be getting heavier again - Complex bindings, big skis, stiff boots, all oriented towards downhill performance. That's fine, but there's plenty of set-ups now that ski well without weighing a ton. I drank too much coffee then weighed all the boots in the cellar - they all fit me so are a fair comparison!
Obviously if you're going uphill you want the Alien. Downhill the Mercury wins easily... but sitting pretty close to each other the Backland and TLT6 are a good compromise and a sizeable saving over the stiff boot (There's also a Backland Carbon "Light" which is...errr...lighter, at a little over a kg)
Ski performance: The Mercury is pretty sturdy and feels like a "proper" ski boot. The Alien doesn't...but it works well with small skis and is brilliant uphill. The TLT is a good ski boot, tune-able stiffness by changing or removing tongues, and can handle a fairly big ski (100mm waist?) I think the Backland skis better than the TLT - it's a bit stiffer and more solid with good flex, and comes higher up the shin. Suits me anyway!
Fit is crucial in ski boots (or in any boot!) I have a very wide foot so the TLT, Mercury and Alien all needed extensive shell stretching and several repeat visits to the shop. Here the Backland is a clear winner - without getting too geeky, you simply heat the Thermo liner and the shell at the same time. While they cook, you stick the usual pads on your feet and prepare for 15mins of very hot toes. Cramming feet into hot shells and inners, the whole boot forms in one go and I've had a comfy fit from day 1. Brilliant.
Only slight grump is that the Backland is a bit fiddly to use, although coming from the super easy TLT everything else is fiddly. Firstly, Atomic use old-style Tech inserts - not the newer Quick-Step-In inserts. They're not as easy to use, but it's fine when you get the hang of it. The boots have a waterproof flap covering the front of the liner (for skinning with the tongues out) It works well (assuming it lasts) but needs velcro-ing in place when you put the boot on. The remove-able tongue allows lots of ankle movement when skinning but is harder to remove and replace than the TLT, needing quite a pull to remove, and a firm shove to replace. It needs careful positioning too - you can easily poke an edge inside the shell. Again, it's OK once you're used to it. The Backland uses a novel cable system for the lower buckle - this works well but (again!) is a bit fiddly. Conventional top buckle, and a separate ski/walk lever which looks a bit like the Alien but only does ski/walk (Both Alien and TLT have combined ski/walk and top clip systems) TLT users will ski off with the top buckle done but still in walk mode...Alien users will be in Ski mode but with the top clip open...until you get used to it.
Overall I'm very pleased with the Backland. I've skinned 1000m+ days, skied piste, windblown hardpack, crust and a few powder turns. Assuming it lasts - more on that as the winter goes on - I'll be very happy with it. It looks like being warm enough, comfy enough, stiff enough, light enough...just right. All very Goldilocks.