I fell into the sponge craze but prefer brushes for the simple reason their easier to clean. I could not wash this sponge and feel confident it was actually clean or dry enough in the center.
It's great to help blend but I'd feel better not using it multiple times to be honest.
After the foundation sponge was recommended to me I brought one. It’s light weight and easy to hold in your hand, you use a different technique to a brush, sponging. I found the effect was smooth finish to my foundation and makeup up did go on smoothly. I only use occasionally as I prefer powder as an everyday cover.
Tips: Use only a small amount and spread, I tended to put too much on the sponge at first and it took a lot more blending.