If handled correctly I actually prefer rpgm, the reason is it's possible to build in a lot more freedom of movement to find little side stories, scenes, and actions. With rpgm you get more of a feel that you are driving the car, with ren'py you are a passenger. With rpgm though there absolutely has to be a very good quest system, those nice little flashing -go here - markers on the map (or in the case purple ones) and a good decent fast travel system, usually the bus, subway or car
I had a good nose around the map earlier and no NPCs are interactive at the moment which was a bit sad but hopefully there will be a bit of dialogue prepped for them later, for inveterate snoopers like myself it is also nice when there is some kind of "bugger off or come back later" dialogue when you interact with a building door, And if based on current corruption levels/ clothes worn affects those dialogues or even opens up little side quests all the better
Anyways good luck dev!