Am confused about the different model numbers on Acer Aspire One Netbooks?

Yes, I am computer illiterate (for the most part). I've decided on picking up an Acer Aspire One Netbook for my business travel. However, once I looked into getting one, I was bombarded with several different model numbers. I looked for the one with the 1gb memory and 120+ hard drive and found a couple with what seemed like the same features, but having different model numbers. For instance, what is the big difference between the AOA150-1625 and the AOA150-1570? Does a higher number mean a better computer? Or is it the same but may be for a different color? I've looked on line for a list of all Acer netbooks but can't find any (Newegg had some listed, but not all). If anyone can enlighten me, I would greatly appreciate it! Thank you