Pros: Ease of use, comfortable, smaller to carry for work, able to pump more over a shorter period of time.
Cons: Several of little pieces for cleaning & assembly
I love my ISIS manual breast pump, it is hands down in my opinion an easier to use pump for any mother who is pumping for their little one. It is easier to take to work and store as it often fit easily into my work bag with several bottles, instead of forcing me to carry my electric pump day in and day out. A previous poster noted difficulties with the flat disk valve and I have never had any of the troubles of the valve popping out while pumping, except if I had too much pressure built up while pumping. This often causes the valves to pop, but can be easily avoided by taking breaks and releasing the seal between the breast and the pump.
The pump came with additional parts for easy replace if anything broke, became worn or was lost.
I used this pump as my only pump when returning to work after my second child, and when I have a 3rd, I will be using this pump again.