GTAIV was much better IMO, it's still my favourite video game.

I loved Liberty City in GTAIV because it was more gritty and felt more like real criminal environment. Organized crime was well researched, you had the 5 families plus a family based on DeCavalcante and other ethnic gangs/OC. Bohan (Bronx) was a cool ghetto, Hove Beach (Brighton Beach) felt like propper lower middle class crime infested immigrant neighbourhood and Alderney (New Jersey) had that Sopranos vibe. GTA V just feels like you're on a holiday compared to that.

I also like Niko as the character more and could relate to him because I'm Slavic and non-American. But he's not only cool because of that, he's a badass criminal, served in the army and is a hired hitman. His story and character felt real, plenty of Serbs became ruthless criminals after the war, many of them went abroad. The story in general was much better in IV. V characters don't really convince me, Trevor is over the top.

I feel that GTAV moved too much away from the criminal theme.