I have logged on a full season and many hours with the 013 Smartbar. My impression, it's one of the best I've used.
If you keep the adjustable ends clean per the Airush instructions, seizing isn't an issue. I clean (soap and water) and re-lube the ends with a dab of lanolin grease (aka nipple cream
found at any pharmacy). I'll do this every third or fourth session and it takes minutes to do.
I have one bar for two kites and it's switching the length is quick n easy. Just be careful not to get sand inside the tubes. Having one bar saves space and money. It's great for travel.
I love the Airush safety system. After owning the Cabrinha's, I find it works just a little more smoothly, and is easy to reassemble (a night and day difference from the 012 and on Cabrinha's).
The depower straps are simple and function well. I tried the North cleat system and I find the strap system easier. I hear the Airush depower handles are harder to reach if you have short arms, I do, but I don't have a problem with it.
I've tried the below the bar adjustment systems. While they're a nice idea on paper, I find them too difficult to adjust. I suppose it's all what you're used to and some will disagree.
Both the North and the Cabrinha bar itself are very comfortable. The Airush finger grips seemed a little "different" at first, but it's not something I notice all that much. I do question their function however. Like the grip on most bars, the Airush is soft enough and "grippy." Why do you need finger idents? Is it some sort of marketing/design distinction? If there is one thing that I'd prefer on the Airush bar, making it nearly perfect, is having a smooth bar without the bicycle style finger grip. This being said, again it's not really an issue, I just find a "smooth" bar a bit more comfortable. And the Smartbar grip, unlike some of the Slingshot bars (I thought I'd need gloves or well calloused hands - nice bar though) is soft as any so it's easy on the hands.
I've have no issue with the softness of the Airush lines. And not to slam Cabrinha, but up until recently were their lines had the pliable equivalent of "yarn". I found them to tangle quite easily compared with the Airush and the North lines.
Since were talking lines, the Airush system includes and adjustable line length system (to run different shorter line lengths if you so choose). I've never messed with this, but it's another option I have...Or if for some reason you snag or damage a section of your line, there's no need to replace the whole line or sets of lines. Just purchase a new section. Nice.
I also like the plastic coated line protector running through the center of the bar. Cabrinha has the same. It cleans up everything quite nicely and it really does protect the lines to increase longevity. I've witnessed my friend deal with line wear on several occasions on his North bar.
The Smartbar is not only functional, but it has a solid overall feel. Contrary to this was the feel of a Switch kite I demoed. The Switch bar was certainly functional enough, but it had a flimsy feel about it. It wasn't the bar itself per se', it was the whole system. North, Liquid Force, and Cabrinha, also have a very solid overall feel.
My impression of the Airush Smartbar on a scale of one to ten:
Bar Comfort 8
Value 10 (one bar is worth multiple bars)
With all the top bars out there, you could do worse than the Airush Smartbar.