1. Anodized aluminum in my opinion will always lend itself to being a slicker call. Some guys say not to scratch it up, some recommend a light abrasive such as a green scotch bright pad, or really fine sandpaper (400 ish grit) and you can also condition your striker tip slightly. Also try using a little chalk on the aluminum surface if you would rather not scratch the anodizing off.
2. Regardless of the material the pot was made from, all striking surfaces will have a noticeable difference in the way they sound. Experiment with several to find what you like the best.
3. Everyone will have their differences, but I'm only speaking for myself, I prefer ceramic, crystal, and titanium