The other day, Douglas Cole posted a game summary in which his character missed a lot in D&D. I've experienced the same in Swords & Wizardry.
And as a GM, I have had a lot of attacks "whiff" in GURPS - either miss (not that common) or hit but get warded off by the defender (much more common.)
I find that whiffing in D&D feels a lot different to me than whiffing in GURPS. Reflecting on this a little bit, I think this is because of two things:
2) Baked-In Options.
When I whiff in a D&D game, I pretty much start to feel useless until I start hitting again.
When I whiff in a GURPS game, it's a little different. First off, most of the time the "whiff" is the net result. I still hit, I still manage to land a blow. My opponent must do something about it. If the enemy Blocks or Parries, well, I'm draining defenses from the target. If he Dodges, I'm forcing movement which potentially could mean falling if he Critically Fails. Maybe he'll Retreat and give up space I want to exploit.
And if I keep whiffing, I can up the ante with Feint or Deceptive Attack or flanking or switching attack modes to something that at least potentially changes the equation. Access to those options really changes the dynamic of what I feel like I can do if necessary. I feel like I have more control, and it's not as luck-based.
DR matters as well - in D&D, once you get hit, you're hit. The blow tells as well as if you had no armor at all - the armor factors into how many of them land. In GURPS, armor factors on hits by reducing them. It might even reduce them to zero. But I find when that happens, my mind starts to turn to, what can I do that isn't impeded by armor? And many options present themselves.
In D&D, in short, I feel like when I miss, I'm useless and my best bet is to hope for better rolls. In GURPS, if I miss because of skill, I can take options to hit more often, and if because of defenses, options to reduce those.
You might say that in D&D-based games, you can try anything. You can explain what you want to do to the DM and he or she will rule on it. But that's true in GURPS, too, to the same extent - you can try anything, and it's equally up to the GM how that goes. But the combination of baked-in options to choose from coupled with a higher hit percentage, which is then coupled with an active roll for the defender to see if it lasts despite counter-action, makes me feel more involved.
That's pretty much what it boils down to - in a straight-up fight, I feel in D&D-based games like my best tactic is to roll better, and I feel a little frustrated and useless when the rolls don't let me hit. In GURPS, I feel like I've got more decisions to make, and that I am less frustrated when it nets out to the same thing - whiffing.
I think this probably says a lot about why I prefer the game systems I do - the more combat is an interaction of factors and not an abstracted one-roll resolution, the more I enjoy combat. And since combat is something I find especially fun in games (and really fun in combat sports in reality), that drives a lot of my enjoyment.
None of which is to say I'm not looking forward to my next D&D game and next S&W game. It's just that I think I have a handle on why whiffing there bothers me more than whiffing in my GURPS games.