I like Successors better, but I don't expect that to be universal. (I like the improvements in many of the rules in Hannibal vs. We the People, but I don't strategic situation nearly as well.)

Other than the situation there are many changes in the game from Hannibal to Successors:

• card based combat is eliminated for a dice based CRT.
• Fleets and naval combat are added in rather abstract manner.
• The rules don't force a choice of movement vs. event card--you are are allowed to move all of your generals each turn and also play (or discard) a Tyche (i.e. event) card.
• Victory conditions are both unusual and somewhat controversial. It involves keeping track of both Legitimacy (points for political reasons: marry into the royal family, taking Alexander's body back to Pella, not attacking anyone except the usurper (i.e. current leader) and VP (gained mostly by controlling territory.
• Successors does has more fiddly rules: Independent armies that move on the board, slightly rules for converting garrison (i.i. PC markers) in the movement and surrender phases.), difference between Prestige and Legitimacy, more unit types--some appearing only one counter, etc.
• There is inevitably going to be more downtime between turns due to more players and the increased amount of game mechanics you have to perform.

But I enjoy it.

Is it the better at 3 or 4 players ? 4 is certainly best and it is playable with 3, but not really with 2 players. How long time for a complete game ? Plan at least 5 hours for a full game with experienced players (longer for newbies.)