Using this does take me a little longer to have everything blended in, but yeah it is worth the extra minute for a more natural and seamless looking finish. I did think having an oily base that my foundation would move around a little more in the day, but thankfully it is still lasting just as good as normal with a little powder mid way through the day.
I like to dampen the sponge first and then use tapping motions to let my foundation sink in and blend into my skin (anyone else sick of the word blend?). My foundation is lasting just as long, the finish is a lot more natural than what I'm used to from the expert face brush, so for everyday it is perfect for providing a flawless looking finish. When I need more coverage I'll still be using the expert face brush, but when I'm wanting a finish that is natural and provides a finish that really looks like skin I'll be using this.
I think if you like a full coverage this may be more useful for blending out other cream products, I have started using this to perfect any contouring and it works really well at making it look as natural and as perfected as possible. I think personally this is needed for anyone that wears foundation, or likes to contour. Oh and I can't forget to mention how old school it feels to be using a sponge!