Akai's turntables aren't highly sought after, and for good reason. I found some pictures and specs of the AP-003 online...looks like a lower-end, mass market design that's largely unexceptional. That's not to say it's horrible...if you just want to dip your toes into analog, it'll probably do just fine. Equip it with a cartridge from the Ortofon OM series (OM stands for optimum mass -- designed to work with a wide range of tables) and take it for a spin. My guess it that it will sound as good as an entry-level CD player in most respects. As for a comparison to the Dual CS505-2, that would be a superior machine but not mindblowingly so. Their ULM tonearms were nice -- provided you outfit them with a high compliance cartridge. The suspended design may also be an advantage. If you already own the Akai, try it out and see what you think. If you want to get serious but don't want to spend a bundle, I have two words for you: Rega P1. $350 with cartridge ready to roll out of the box. Now THAT will be a major step up from both the Akai and the Dual. And you have a built-in upgrade path. For a few extra bucks, trade the stock platter for the glass platter from the P3. Add a Ringmat in place of the stock felt mat. And upgrade the cartridge to a nice moving coil in the $200-400 range down the road. It's a smart investment if you see yourself sticking with analog.
Good luck!
Good luck!