Both pens are certainly a pleasure to use. However, they each have their own qualities and it really comes down to a personal preference as to which one you'll enjoy more. There aren't any fancy gel comfort grips on these pens, but the shape of the tinted part of the barrel is ergonomic enough to feel quite comfortable in your hand.
The difference between the two becomes apparent with the first few words you write. The Ageless line is thick and muddled while the Timeline's line is crisp and clean. Surprisingly, the Ageless is remarkably smooth for a ballpoint. I rarely pick up ballpoints anymore - I just prefer a smoother write - but for some reason the Ageless is something entirely different than what I've come to expect from ballpoints. Now, don't get me wrong, certainly I'm not saying the gel ink Timeline pens aren't smooth. I'd say the smoothness of the gel ink Timeline is comparable, if not slightly better than, the liquid ink Ohto Fine Ceramic Rollerball 0.5 mm pen - and that's one of my favorites. All I'm saying is that the Ageless might change your opinions of ballpoints.
From a purely aesthetic perspective both these pens look absolutely cool. From the innovative twist mechanism to the sleek, futuristic design, these pens will surely turn some heads when you use it.
If you had to get just one, which one would you get? It's an excellent question and it really comes down to personal preference, in my opinion. Does your work require more precision in your lines? Can you sacrifice a little precision in your lines to get a super smooth flow? Do you detest ballpoints no matter what? It's hard to argue for the Timeline with a $45 price tag - you might be inclined to say there are slightly better gel ink pens for a cheaper price - but, boy, if you like gel ink pens, I think these are some of the coolest out there. (My advice? Get both... =P)
Stay tuned for pictures =) ....