WARNING: LONG POST
First off, the boring stuff. Both of these knives are good knives. There is nothing functionally wrong with either of them. I’ve used both of them and have come to the conclusion that, for me, the Salt 1 is a better EDC knife all around than the standard, sabre ground Delica 4. These are some of the more popular knives in Spyderco’s line, so I won’t post pictures or specs- mine look no different from anyone else’s and have the same materials everyone knows and loves. Both were purchased from Amazon.

Now for my opinions. These two knives are VERY similar overall. In fact, the Salt 1 is basically just a Delica 3 with a hollow ground H-1 blade, rustproof hardware, ramp jimping, a (supposedly, haven’t tested it) titanium clip and a yellow handle, plus “Salt 1” molded into the handle where “Delica 3” once was. The clip is different from the Delica 4 (hereafter known as the Delica) in that it is longer and is attached differently, using Spyderco’s old lanyard tube attachment method (my own terminology there, but it gets the point across). The ergonomics are almost identical, the butt of the Salt 1 (Salt) is squared off where the Delica is more pointed. The Salt does not have liners, while the Delica has milled steel liners. There is no jimping on the handle along the lockbar of the Salt. Essentially, they are almost the same knife, with very small functional/technical differences and very few aesthetic differences.

But I’ve carried and used the Salt four times as much (to be conservative) as I have the Delica. I simply find it to be better. Why? Well, the Delica is heavier. Those steel liners, though they’re milled, add a noticeable amount of extra weight to the Delica and throw off the balance. The Delica’s balance point is about at my middle finger as I grip the knife, while the Salt’s is right in the middle of my index finger, which (subjectively) feels better to me. Also, the Delica is not as comfortable as the Salt- when a design fits the hand as well as the Salt fits mine, one notices the tiniest of differences. The Delica’s design is ever so slightly different, and ends up having the effect of putting the first choil bump right under the meat of my middle finger in a sabre grip, while the Salt simply melts. The addition of one extra millimeter (by my eye) of space in the Spyderhole allows for considerably better deployment- in conjunction with the longer clip, which aids indexing and positive retention upon deployment (as seen in some old Spyderco Clipit ads IIRC), the Salt snaps open more comfortably. I don’t feel as though I’m going to slip off the handle or out of the hole like I sometimes do when snapping open the Delica. Speaking of the clip, the Salt is stronger on my example, and grips the pocket fabric better both because of more tension and because the Delica’s clip falls on the smooth logo (I’m positive that’s intentional, and it’s not necessarily a bad thing), while the Salt’s lands right in the middle of some volcano grip. It also allows a natural three finger indexing if that’s important to you, while the Delica’s requires the user (me at least) to scrunch up their three fingers a little more on the clip.

The Boye dent on the Salt is considerably more pronounced than on my Delica, which means that I have to focus less on the Salt when I’m closing it one handed (press and flick method) without looking at it- just slide my thumb along the side until it falls into the dent. Not as easy with the very subtle dent on the Delica. Tiny difference in the long run though. Both work.

The Salt cuts better. It’s hollow ground, which means that there’s quite a bit less steel behind the edge than on the flat sabre ground Delica, even with very comparable stock thickness and grind widths. That thinner edge lets the Salt slip through cutting medium-whatever it is- with less effort than you would need with the Delica. The FFG Delica will cut better than the Salt, however. The H1 is softer than VG10. That means that you’re going to have to touch it up more often, but it’s incredibly easy to touch up.

All of these are infinitesimal differences in the long run, and both knives are fantastic knives at the end of the day. However, when you get to the level of greatness in category that these knives have attained, the tiniest of differences can make or break one over the other. The Delica comes in at #2 for me. YMMV.
Any opinions are welcomed.