I have one. It’s made my machine so much better. Once you find a grind setting and dose weight that works well for your beans, you get perfectly reproducible shots.
What Grinder do you use? I have a Gaggia as well been using Baratza Encore but it’s not really for Espresso but now they have the Encore Esp for espresso
I've got the Virtuoso. The '586 (?) model with improved burrs. It's bulletproof. I did have to replace a few of the plastic parts that act like mechanical fuses when I tried to grind a batch of coffee that had a pebble in it.