Lots of Grip threads on here, and every one has someone complaining about fit in them so I wasn't sure where to post this. I figured here was the best place since the thread title mentions fit specifically.
I purchased the A-frame in November. I already had the L-frame and loved it, but wanted a bag that could fit another disc or two and the A-frame seemed promising. I haven't played since I got the A-frame due to health reasons but I will resume play in late April and will have a lot more comparisons by then. For now, here is the main thing I noticed between the two bag styles that may affect fit for some people:
The A-frame bag is taller and as a result the straps at the top attach a couple inches below the top of the bag, lower than the L-frame. For those that like to have their bag ride high (like myself) this can be an issue. With the L-frame bag I can adjust the straps pretty high for a tight fit, and when I do that the handle of the bag would rest against my neck. No big deal, since the straps attach close enough to the top of the bag that there is plenty of room for the handle to flex back over the top and not apply any pressure on my neck. No discomfort. With the A-series that is not the case. Since the straps attach a couple inches below the top of the bag, the handle of the bag can't flex back like it can in the L-frame... They push up against the back of the bag. Therefore if you adjust the straps for the bag to fit snug and ride high on your back, the handle will dig into your neck causing some discomfort. To correct this you would need to loosen the straps so there is more slack up top, but then you lower the bag enough where it's no longer flush against your back and is riding more on your a**.
Pictures of the handle in case you have problems picturing what I said.... Notice how much more travel the L-series has in the handle compared to the A-series.
Last but not least, any claim that the A-frame was redesigned to make it more stable is wishful thinking. It's just as unstable as the L-frame except the A-frame is more likely to fall on its face (where the disc flap is) and the L-frame is more likely to fall on its back (where the straps are).