The first predator was the oldest. Stephen hopkins, in old magazine interviews, described the pred in 2 as younger, leaner & more reckless, he could obviously have taken harrigan out on numerous occasions but "plays" with him and then gets over confident, enter the shotgun !
The predator in 2 defo looked the coolest with the best weapons.
With regards to how tough the preds are in the first 2 movies. The problem is that they are so advanced they could take the cast out quickly if they chose but obviously this wouldn't make much of a film ! & we know they had to lose, although i root for them !
That's why it was good to see the pred side with us in AvP. Regarding the preds in AvP, they were definitely the youngest. I didn't mind them being bigger, but their faces just weren't right, just too clean. Hopefully the pred in AvP2 will be more like pred 2 & it looks like it could be greener like in some of the comics ??