I have the G21SF, and I like it. No malfs, yet, though only ~200 rounds fired. The grip was a little uncomfortable at first, not so much due to the overall size, but from the width at the top of the backstrap. Interestingly, for such a large grip, there is no scalloping there, at all. My hand actually got sore the first few times I handled it, because it creates a little bit of a pressure point in the web of my hand. With a firm hold, the soft pad in the web of my hand gets stretched back and up, so that it hugs the "beavertail." Fear not, though; at least for me, I got used to it very quickly and now find it all day-comfortable and wouldn't have it any other way, because I feel that it aids in control. Actually, it reminds me of the feeling I had the first time I tried the high thumb hold (which I quickly adopted) on a 1911.
I absolutely love the trigger. Out of the box, it had some variation, where sometimes there would be a little creep, almost like a false break, followed by a crisp but slightly stacked break. I found it a little disappointing. But after some breaking in, this has all but completely disappeared. Now, it is near uniform, with pretty much zero takeup or creep and a clean, consistent break. Actually, it seems like you can "step" the trigger if you use both hands and work it back slowly, so what feels like the "working break" is actually the first part of the trigger travel. So when this "breaks," the rest of the very short travel that unlocks the sear becomes almost like part of the overtravel. It's like a smooth double-action revolver trigger which has a "point of no return" after which you get a smooth accelerated pull ending in an invisible break - but it's compacted into something like 1/8" of travel, and the point of no return is at the very start. I love it.