I'm a newbie as well, so don't just go with what I say, but if you read the specs in the description for each watch at the dealers web sites, you'd notice all sort of differences - different movements, different straps, and some have AR coating on the Sapphire crystal and some don't. Sometimes the reps are closer to the original, and sometimes they have specific flaws. You'd see references to 4th and 5th generation on the POs since the newer ones have corrected some older flaws.
Also, reading all the posts you notice some dealers provide much better support in case you have any issues with the watch you receive - the good support alone may be worth the additional cost.
Good luck.