The advanced is more similar to the style used in the huspital as it has a 'pumping' action for about 2 minutes to stimulate the milk. Then, after the minutes, it does the gentle motion to express the milk.
I was originally going to get the pump in style but hten upgraded it - as I liked how it got the milk flowing very well. I have twin girls and used it when they were very young and then when I traveled.
I nursed most of the time but also have a home business when I do home shows, etc. My girls were 4 weeks early so I wanted to make sure I established a good milk supply (which it did as I had PLENTY).
Other than that, I think that is the difference. I knew with twins, I would want to pump at the same time. With my son, a much cheaper pump was just fine as I only pumped on occasion.
I liked mine - but am already done with it:)
It still saved me LOTS of money on formula - as now I buy a can a week for the girls ($80 a month!).
So, if you plan on nursing for at least a few months, your money will be well spent as the formula you would pay otherwise would pay for it.
I had just a ISIS Pump ($60 or so) with my now 2 1/2 year old son. That worked just fine. I had thought upgrading my pump would help my milk supply longer.
CONGRATULATIONS!!