Don't know much about ultem, but I really like the DEKA IF the scales are upgraded from the regular plastic ones to g10. It rides in the pocket without hogging up space, solid little knife. now.
I also have a set of skinny XL titanium scales from original goat that i haven't even tried yet, but the extra 3/16" or so of length on those looks like it be a real plus. As far as value goes, i can't say this knife was a great value and is the only knife I have ever had where i felt the need to spend $ on scale upgrades. I have $200 worth of extra scales on a $135 knife. lol
As is, with just the G10 scale upgrade (which IMO is mandatory if it has the regular plastic ones) i have $195 in this set up. hmmmmmm. There's better knives out there for $195 or less, the Bel Air carbon Fiber MC being one of them. There's nothing to upgrade on that knife but maybe the screws. It feels like a Ferrari or something the way it operates though. Holy cow is it slick.
I only gave $175 for that little jewel which seems like a bargain now, although I could reason that it fills a slightly different role than the DEKA. Out of the 2, I'd pick the DEKA for a more robust working knife.
One thing I like on the DEKA over the Bel Air, well maybe three things...is the fact that i can figure out the thread pitch on all the hardware. It also uses T8 throughout, that's cool. Also the washers could be an advantage in very dirty chores where you'd want something easier to clean up.
The DEKA has a huge pivot screw thread with T8 torx head, and a honkin' 8-32 x .25" long thread. Body screws are also T8 and 2-56 x 1/8" long threads. I like this.
The Bel air uses some strange screw threads. The pivot screw is T8 but the thread pitch is something alien to me...they aren't 6-32 they aren't M3.5x.35. They literally fit NOTHING in my thread gauge sets, metric nor standard. No idea. Maybe 6-40. Little T6 Body screws *kinda" thread into 2-56 but seem loosey-goosey, won't fit any of the tiny metric gauges or standard i have. If Kershaw ever stopped making these special screws I guess you'd be foxxed. I Don't like this.
I'm glad I own both actually. The Deka seems like a bit heavier duty overall, perhaps it would be less persnickety in extremely dirty, muddy, bloody tasks.
Looking back, i would have/should have grabbed the 20cv/g10 one on a sale and been done with it. IMO, the 20cv with G10 > MC with flimsy plastic.