For the most part, I've found the flow rates to be pretty good in the field with the sawyer, say around 2.5 min/liter range. I'd say that's about the same or just a little slower than what I get with tap water at home. I have to condition this statement with the aknowledgement that I tend to find and filter pretty clear water sources to begin with and/or pre-filter, so this helps to keep things filtering quickly.
If you don't pre-filter or you have really turbid water, you will notice a definite degradation in the filter's performance over time. On my last overnighter, we got a bit of rain/hail/snow and the creek was running super muddy. For some reason, I wasn't thinking and filtered the water through the sawyer without pre-filtering first. It worked fine for the first two liters but when I went to filter more the next morning, it ended up being pretty clogged and slowed down to an agonizing trickle, probably on track for a 10-15 min/liter pace! Needless to say, I canned it and used some back-up chemical treatment for the walk out since I couldn't seem to sufficiently backflush it in the field. I had to do some serious backflushing at home to return the filter to its peak performance, but now it seems to be back to normal.
THREAD DRIFT WARNING...Just a FYI Travis, I posted a couple of pics of my trailstar with the pentanet 2 under it recently. Not sure if you saw those, but I think you had told me you were interested in that combo.