First post on this forum, but I own the Shield 9 and the P290rs, and just shot them side by side a few days ago, so thought I'd offer a few thoughts.
Trigger: The 290rs is definitely long, but is smooth with very little stacking and breaks clean. My wife's primary range gun is a Sig2022, so both of us have a lot of experience with a DA Sig trigger. The biggest difference is that the reset on the 290 is way longer (basically all the way out) vs the shorter reset on the 2022 as it kicks into SA after the first shot. After adjusting for this, it was very easy for both of us to shoot the 290 well and with reasonably fast follow up shots. The Shield is a much shorter pull, with a bit of a "wall" at the point of the break. I shoot an XDM 3.8 compact 45 most of the time, so the Shield's trigger just feels like a stiffer version of that. Since the frame is also smaller on the Shield, I found that moving more of my finger through the trigger guard so the trigger face hits closer to the joint (rather than the middle of the finger pad) helps with comfort and also gives me a bit more leverage to get the Shield to break. All that being said, we put several mags through the 290 the other day, and when I picked up the Shield, I definitely experienced a "surprise break" as my trigger finger was still thinking DA...
Accuracy: I understand that these are SD and not target guns, but the 290 is definitely more accurate for both the wife and me. Out of the box, we both shot groups of well under 2" at 5 yards with the 290, and just a little wider at 7, using a basic Weaver stance. I can pretty much hit what I want with the Shield, but was shocked at how much of a tack driver the 290 is. As somebody mentioned earlier, I tend to shoot the Shield slightly left as well.
Sights: Perhaps this has something to do with the accuracy
but the even in daylight the night sights on the Sig are way better than the Shield's white 3-dots. As a side-note, I used glow-on paint on the front sight of the Shield, which helped a lot, but the Sig still wins.
Recoil: This is something I haven't seen a lot of comments on, but the recoil on these two guns is very different. The muzzle flip / jumpiness is more noticeable on the Shield. With my wife especially, she felt that the Shield was bouncing all over the place as she was shooting. I certainly felt that the Sig was quicker to get back on target. On the other hand, the Shield is more comfortable to shoot, especially as the round count gets high. My personal and unscientific opinion is that the bore axis and/or center of gravity differs and is higher on the Shield. This causes the recoil to produce more flip. The Sig stays down and just pounds you in the seam of the hand just between the heal and the palm. Basically right above the fat area below the thumb where the back of the grip sits. I have put 600 rounds through my compact 45 in under 4 days and never experienced discomfort like I did with under 100 rounds in the 290. That doesn't make it any less of a fantastic SD gun, but extended range visits may require some Advil.
Comfort to carry: This is a toss-up, and really depends on how you carry. In a combat-cut IWB where the grip is directly against the skin, the Shield has the advantage, as the sandpaper type grip on the 290 will rub you raw. Pocket carry favors the Sig with its smaller dimensions. Btw, it shoots just fine with a pinkie tucked under the smaller mag (which is pretty much required for pocket carry), but the extended mag is a little more comfortable to shoot.
Reliability: Both were a little stiff at first (especially the Shield), but they run with no issues, except the occasional failure to lock back on empty with certain mags (both guns). I'm pretty sure that will resolve itself as I break the mags in. Given all the negative press about the 290, I just thought I would throw that in and mention that the 290rs ran great right out of the box and had no FTF with some cheap target ammo. I haven't put sd rounds through it yet.
Bottom line, both are great for what they are for. My wife shoots DA/SA a lot and prefers the Sig, despite the more painful recoil. I like the striker-fired Shield even though I am a little more accurate with the Sig. I guess when it comes to the type of trigger, in the heat of the moment I want to go with what I know will be more natural for me.
Hope this helps.
