BEST: I know tons of people sang the praises of this game too much, but they're not wrong. SR 2 improved greatly from SR 1 and offered so much open world content that no other open world game, new or old, still can't do.
1
Saints Row IV
#2: If the game wasn't planned dlc for the third, this would have been the best game in the series
2
Saints Row: The Third
#3: Introduces the series to a more wacky and goofy side. The gameplay is fun as hell and offers tons of creative things to do. The story isn't that good though.
3
Saints Row
#4: The story, writing and characters are still great nowadays, but the gameplay hasn't aged for the best and the game suffers from technical issues that boggle it down.
4
Saints Row: Gat Out of Hell
#5: As a dlc/expansion for Saints Row IV, it's fine. Probably won't please everyone, but it has some cool moments.