Gta 4 complete pack worth it? Haven't played it yet and kinda want a GTA...
Performance wise, GATIV is a terrible port for some. For others it randomly runs decently, its really schizophrenic in who gets lucky.
GTAIV story wise is enjoyable if you like older, world weary protagonists forced into violence instead of cocky 20 year olds out to prove themselves (basically its a proto-RDR).
The Episodes:
The episodes were planned ahead of the main game so there are minor guest appearances and mentions by the characters throughout all three.
The ballad of Gay Tony introduces a new weapon(I think its only the automatic shotgun that breaks the game balance.. sorry it's been a few years so I can't remember any others.) but every character is uninteresting or unlikeable, except for maybe Amir if you're into charismatic fools.
The Lost and the Damned has cookie cutter characters and the story arc becomes obvious about an hour in. They introduced biker gang specific mechanics and weapons, but they're not really useful.