I can attest that the Revelate bags are very well made (and I make bike bags too, so I'd know!), and they do not sway even when loaded. I haven't ridden with one myself, but have ridden with others who were using them and have poked around "under the hood" as it were.
Part of why they are so stable though is that they compress everything down so it's not moving, so if wrinkles are a problem, any bag of this type is not the solution. The other drawback is that if what you want is at the bottom, you have to take out everything else to get it; but if it's just shoes and a change of clothes, that won't matter.
The other type of saddlebag that's popular with long distance folks is the traditional "transverse" style (and in interests of full disclosure, I do have a commercial interest in those). They come in larger sizes, they are easier to get stuff out of, and stuff doesn't have to be squished in there. But they require either a saddle with loops on the back for a saddlebag, or an after-market mount to carry them. However, some of the after-market mounts have quick release features that are very handy. I use a Carradice SQR Uplift mount for mine, which lets me take it off or put it on in about two seconds. The downside of that mount is that it's heavy, although still lighter than a whole rear rack. I mostly use it for brevets or other long rides, though, not on the commuting bike.
I use the saddlebag that I produce for commuting sometimes, but honestly my preference for riding around town is just to use a rear rack and carry around a large pannier (usually just one, but sometimes two) that I can dump my stuff into. Much more convenient, and it makes it much easier to do un-planned errands, grocery stops, etc, plus I often need to carry around more than would fit in most saddlebags anyway. It's heavier and way less aero but I'm just going from red light to red light anyway, right?
