I have twins and spend a lot of time nursing and pumping, I have very little free time and felt I am wasting time pumping.  Then I bought this bra!  I have been using  it every time I pump for the last 4 months several times a day (my babies are 6 months old), it has paid off a long time ago.  No way, I would be able to continue pumping at work without it - I would have given up a long time ago.  I talk on the phone, eat my lunch, browse the web, etc. while pumping - it's a time saver.
Just make sure your milk supply is well established before starting to use it every time - it does prevent all of the milk from being expressed due to compression, sometimes I finish off with manual expression or pumping a few minutes with the bra off while massaging the breasts.