This dilemma over the choice of these two seems to be a recurring theme in several threads bouncing around for people who seek out quality production Ti frame-locks . The good news is whichever one you choose, it and you will be a winner, and...will probably lead you to buy your second choice shortly thereafter.
I started with the Sage 2 (and 1), and like all Taichung produced Spyderco's, was astonished at it's fit/finish and overall quality feel approaching popular mid-techs...just an incredible sophisticated folder and exceptional deal at current going prices. The only downside for me was it's handle to blade ratio disparity and minor difficulty accessing the rear of the blade to sharpen, since there's no sharpening choil.
Then, liking the Sage 2 so much, I bought the Techno and was immediately even more impressed! With no finger choil (but a great sharpening choil) there is almost as much useful cutting edge as the Sage but the CTS-XHP steel IMO really is on a higher level than S30v. This steel sharpens even easier than S30v w/o the chipping concerns and when sharpening both blades at the same 30degree inc. angle, finishing on the same EF DMT stones...the Techno actually slices just as well as the Sage...and sometimes I believe even better? Further...it holds a shaving edge much longer than S30v...
There seems to be a kind of natural lubricity to XHP that when finished on a high grit stone, simply makes this steel glide through paper and cardboard without feeling the same scratchy sort of sound/feel that I typically get from S30v...it's really incredible stuff. Combine this with the dramatically thin edge behind the cutting bevel and this is one deceptively good slicer. The only knock against it is deep cutting of harder mediums due to spine width.
The Techno, to my eye...is gorgeous! The immaculate stonewashing of not only the scales and blade, but even the screws and clip really showcase Taichung's attention to detail...even the blue G10 backspacer is so perfectly fitted between the scales that it almost seems to be part of the titanium. In contrast to the elegant look of the Sage 2, with it's hidden lock-bar relief and soft even bead blasted finish and satin ground blade...the Techno looks like a beefy, manly, rugged, precision tool with it's outboard lock-bar cutout and stonewashing that actually starts to look better with age as a very subtle mottling starts to emerge. As good as the Sage 2 is...and it is very good...the Techno just speaks to me on another plane. (And apparently many others considering it's rabid fan base).
Slightly thicker and incrementally heavier than the Sage, the Techno still carries well and can even be carried in the fifth pocket of jeans. At this point in time, I can't imagine another production folder with this design aesthetic and level of F & F replacing this as my favorite EDC. I truly love this beefy little folder like no other knife I have ever owned.
EDIT: One other thing...out of a year of using both extensively and much obsessive opening and closing...the untreated Sage 2 lock-bar has moved slightly from new at approx. 30/35% to around 40%...The treated Techno's lock-bar is the same as the day I got it! Something to consider when buying, and more importantly...using...a Ti frame-lock.