I have two Salsa Airs--a 26" bought on a river cruise at the Rimowa store in Cologne in 2012 and a 29" at Kaehler Luggage in Chicago, for an upcoming Paris trip, in early 2014. They are both unbelievably lightweight (6.4 and 7.1 lb respectively) and I've never come close to overpacking them. They spin and roll effortlessly and are (mostly) a joy to use--much better than the heavier knockoffs like Heys or London Fog. And only the Salsa Air offers the dual zippered mesh dividers--a godsend if you need to live out of the case but have no space on the luggage rack in your room to safely open it flat; with only one half covered by the zippered mesh (as on the cases with one mesh and one elastic strap or tiedown), if you have to prop it up in an L shape stuff will constantly be falling out.
Unfortunately, the handle on my 29" has never locked in place (a PITA when rolling two bags at once) and one of the zippers on the interior mesh dividers usually comes apart (one even lost its pull). Fortunately, each divider has two pulls so it's no major deal. I have a long business trip to Spain coming up, requiring enough nice clothes and shoes to get me through 10 days without doing laundry (and no, I do not wash my clothing in the sink at nice hotels!). I would dearly love to get the 32" Salsa Air, but it's an inch over the "oversize" cumulative limit of 62". Yet it weighs only 7.8 lb.! I will be flying Business Class across the ocean--and Iberia allows three free bags of less than 23kg ea. I find it utterly ridiculous that they'll let me check 3 30-inchers for a total weight of over 140 lbs., but not a 32 and a smaller bag that together, fully packed with anything short of bricks, wouldn't even come close to 100! And to add insult to injury, no matter what size and weight, within Spain Iberia offers only steerage....uh, Economy...with ONE free bag, period! Only Southwest lets the size thing slide, so long as the bag is underweight.
So I would highly recommend the Salsa Air over the Salsa or Salsa Deluxe--it's less expensive, no less durable (they'll fix my handle and zippers for free under warranty), and way, way lighter. In my experience, the fripperies that come with the more expensive models--e.g., add-a-bag strap (never used it on any suitcases I've owned--strap a bag onto any suitcase and it'll be unstable and tippy unless you pull the bag on only one set of wheels--tiring and defeats the purpose of a spinner), detachable suiter (adds weight and never holds enough hangers), H-shaped handles, tie-down interior straps--have been unnecessary at best and a disadvantage at worst.
So to be safe I plan to get the 30" model (holds 10 L more than the 29" but weighs only 7.4 lb.) to replace the heavier cheapo Heys from Target. And when the handle on my Swissgear soft side carry-on spinner (a freebie) finally bites the dust (likely at the end of the domestic trip I'm currently on), I'll probably get the equivalent dimension Salsa Air carry-on--lighter and holds more. (The Swissgear's only advantage is a laptop compartment accessible from the outside, but I'm TSA Pre-Check anyway so I don't need to remove my notebook at security).