I learned on my dad's Rockchucker. Then I bought a Rockchucker. Then a couple years later, I bought a Dillon 650 and I love it. I still use my Rockchucker for my single loaded bullets, cross the course or palma bullets. I'll teach my nephew on the Rockchucker some day, and he will drool over the Dillon.
For .45 I use tight group, although with the lubed cast bullets, it can create quite a bit of smoke. My STI Edge was called a locomotive at the last match. For my .223 55gr plinker rounds, I like either 2460 or BL-C2. With rifle powder your reloading equipment may influence your powder choice. In my Dillon 650 I don't like using Extruded or Tubular powder as much as Spherical or Ball Powder. The Extruded powder can get caught or cut by the powder bar. Also the Extruded stacks and can take up more room in the case. The ball powder is finer though and has a tendency to jump out of the case as the machine indexes. Hope this helps.