Most powerful pump besides hospital grade?

I'm trying to get things together for when I return to work. I am still renting the Medela Symphony pump from my hospital and will primarily use that pump, but occasionally I have to travel for work and will need something a little more portable, that also can run off a battery pack. Since I'm pumping for two, I want the most powerful pump available. Is the Medela Pump in Style, or the Freestyle the next most powerful pump out there, or a different pump than these two? I've heard conflicting info on which one of these two is the most powerful. Thanks!

 

I use the PIS. I have used it off the batteries on occassion and it still works great. I believe my formwr manager used one back when the only place to pump was in her car.

Since I've never used the freestyle (or anything other than the PIS) I can't say which one is more powerful and you should probably take my opinion with a grain of salt. But the PIS definitely gets the job done for me.

PS - I got my PIS in early 2010 and used it while at work for about a year. I've been using it for about 6 months with the twins. It's performance has degraded some but not tp the point that it has caused issues so it does last if you think you will need it for an extended timeframe.