is a old psp still good? example-no skype

i am looking at buying an older (phat) psp from a friend. i am worried that it might be a waste of money as new features might not be compatable. i just read that the upcoming skype feature wont work on the older model.

so my qustion is- are there other things that the older model cant do? ive read that the slim has more ram: does that make it better for viewing websites than the phat model?

I think it has brighter screen and you can watch tv via add-on such as the psp camera!