Thanks for the replies guys. Looks like there are some mixed results here. I also saw on Whiteblaze that others are complaining about the pumping force, so it is definitely and issue.

For the record, I am 6'-5" (how many times have long time members seen me post my height and said "I don't care"...it's for the newer guys), in decent physical condition (lift light weights), and I pump a liter or two during the day and about 5 after setting up camp. It's the 5 in a row that's tough. I can deal with the force required for 1 liter, but a few liters into the 5 my muscles are burning. My buddy was watching me last time we were out, and commented on how he was glad he got the Miniworks. I will say that if you pump slower, it's not as bad. It goes against the speed claims of the filter though, and makes the filter kinda "one dimensional" in that all one really saves in using it is weight.