The freestyle is ideal if you intend to bring the pump from office to home everyday. I personally liked it cause of its hands free accessories, allowing me to do other things while pumping. You might find this useful in the office, so that you can pump while doing work. It comes with a memory chip so that you can program your pumping style & every time you pump, it will pump at the same suction level and for the same duration. It's ideal for working moms, both in function and portability.
I didn't use the programing function cause I found I was quite comfortable with the default setting. The hands free was great for me, but I guess there are also hands-free bras & things like the pumping pals' strap that will make your ordinary pump hands free too. Before I had the freestyle I was using the pump in style. In comparison, I prefer the pump in style cause I felt it was more silent. I'm not sure if it's just because of my sets, but I thought the pump in style had better suction than the freestyle. There are reviews online comparing these 2 and many prefer the pump in style.
Only downside of the pump in style is that it's slightly bigger and doesn't offer you the hands free convenience. Personally I will get the pump in style & leave it in the office, while direct latch on when I go home.