Sims 1
Pros: the adventure of it all, wholly new gaming territory to be explored and mastered, screenshots tied to house holds with ample caption room-great for telling stories, the little pond where you could feed fish or sail little boats, CC friendly, packs worth the $
Cons: in CAS if a sim skin didn't have a mesh the whole game crashed instead of just no outfit for the sim
Sims 2
Pros: to try to keep it simple... sims had deep and complex personalities, gameplay rich varied and often exciting, CC friendly, screenshots as TS1, obvious the makers cared a lot and put much effort into the game - down to tiny details, got your $ worh in packs, CAS able to produce highly customizable and individual sims, the incredible web site we had that focused on the simmers not the company
Cons: I know there are some, as it's made by imperfect people, but most complaints I've seen seem to be in comparison to later versions that have more advanced technology. For it's day it blew the doors off the competition.
Sims3:
Pros: color wheel, novel ideas in game content and play - world adventures, horses
Cons: sims all look the same regardless of age or gender, loss of story ability with screenshots-all dumped into a common pot, meh graphics, pretty much confined to 1 household per world. I just could not get into this version, which may well be another con. 1 & 2 can grab my attention for hours, especially 2.
Sims 4
Pros: beautiful to look at, CAS, some build mode features
Cons: a legion of them, too many to list and any effort to try would be depressing. We all know what they are as these forums are filled to overflowing with simmers expressing their woes and frustrations.