I had a naked portafilter for a year and half before I figured it out. Tried it a couple of times when I bought it, but it was really messy and I gave up. I assumed the portafilter was just crappy.
After seeing videos of people making good looking shots with it, I tried again and experimented a lot with different grinder settings, less ground coffee, and a better tamper. Now I'm making great looking shots. It was a bit frustrating at times, as it was hard to figure out what I was doing wrong.
I think it's worth it, as I learned a lot by experimenting. I'm not sure my coffee tastes better, but I'm not a pro and I mostly drink it with milk.
Do you think you're good or at least decent at making espresso? Do you want to start feeling bad for yourself and question your abilities? This is the portafilter for you.
I try to be consistent in dose weight and grind settings, but the naked portafilter can be unforgiving about other issues that I might have, such as the tamp and distribution. Since getting the naked portafilter, I've gotten into the habit of using the Weiss Distribution Technique (basically mixing up the grounds with a small knife or fork to try to get more even distribution), and I wouldn't be surprised if I started tamping with a scale some day soon.
What have I become?
Works well and is helping us improve our tamping skills.