Good - for a manual pump.
This is a great manual pump and can work very well.  It stimulates let down within a minute or less for me.  It takes a bit of practice but once you get the hang of it it works well.  However, it is kind of a pain to clean and take apart.  It is also unbalanced on the bottle and always seems to tip over.  I also have a Pump N Style which is much quicker and easier.  This is a good option for occasional use though or if you want to pump on one side while baby feeds on the other (easier than PNS because the tubes get in the way).
Rating: 4 stars