I have both and both are fine knives. The Leek has a more delicate tip than the Ripple. The Ripple is a much smoother knife in opening and is just a fast at doing so. In fact, it is the smoothest opening/closing action of
ANY knife I have ever experienced. I'm not saying that I have tried tons of knives but I have several and fondled many, many more. The Ripple is smoother than any AXIS lock I have tried (710, 551, 557, 943, 707) and smoother than any of my flippers including the JYD II and very smooth Skyline.
Lockup on both is solid. They are both very slender knives in the hand and in the pocket. The Ripple is tip-down only. The steel on the Ripple is Acuto+ which I have no experience with but I hear it is a 1/2 step to a step up from 440C. The Ripple blade is slightly longer and wider and I like the belly on it more so than the Wharnie-type Leek although I do like the Leek blade shape but am just used to more belly. The Ripple has some sharp edges and corners on the handle scales that may catch your skin. I wouldn't call the Ripple "delicate". Its construction is quite solid. The Ripple is no more "delicate" than my Leek in the handle. In the blade, I'd say the Leek would break first since it tapers so thin at the tip.
My Ripple was $76 and my Leek was $40. Ge the S30V Leek and it would be close in price then.
As to which one is "better", well, I'm not the one to tell you that. Only you can decide what's best for you or your friend. I need more time with the Ripple to better make an informed judgment. I've had the Leek for a while and can easily recommend that. But in my limited use of the Ripple, I love it! I can recommend the Ripple too.