Colour: The colour of the 17 is about one shade darker at pale gold while the 24 is at pale straw (so I am afraid of another very inactive or depleted cask). The texture of the 17 shows some fast legs and late medium tears. The 24 shows many fast legs and a few late fat tears.
Nose: The 24 offers that typical fruity Glen Keith profile imbedded in a strong barley sugary and wooden structure. Nicely balanced but not as intense as I had hoped for (yes, the cask was not very active over the 24 years). The 17 shows a stronger aromas profile (from a more active cask) that is centered around grassy-herbal notes. Personally I like the 24 a little better.
Initial mouthfeel: The 24 arrives unspectacular in the mouth with nothing special to mention. The 17 is better here with a warming and slightly coating feeling. Both show no distracting moments (bitter/drying/adstringent).
Taste: The 17 offers a balanced sugary sweet-summer floral-spicy flavours profile that is not overly complex but easy drinkable. Some hints of fruits lurk in the background. The 24 shows more fruits on the palate and (surprisingly) quite substantial roasted coffee and chocolatey flavours (do you know these chocolate-coated coffee beans that are served in some coffee shops as a side snack to your espresso?). That is really adorable, I like that! It is significantly more complex than the 17 and even somewhat layered. Not too bad...and this round goes clearly to the 24.
Finish: The 24 has a medium length finish on even more chocolatey and minty flavours (like "After Eight" in a very light version), no bitter or drying moments. The finish of the 17 is of comparable length and fades out on the same sweet and herbal profile like the taste. It has no bitter or drying feelings either. Again I give this round to the 24.
Water releases more aromas in both drams and turns the 17 smoother and more balanced so I like it much better when reduced by some water (2 points up). The 24 offers more of the chocolate-coated coffee beans aromas when reduced but this drives the dram a little out of its nice balance so I like it better when neat.
Both drams are easy sippable and a fair value for the buck (these days). I personally like the 24 more because of its adorable flavours profile but if you own a different taste I can imagine that you prefer the 17. Interesting that the exhausted cask of the 24 produced nevertheless a fine aromas profile that just is a little too shy - but the chocolate-coated coffee beans I really loved...