BaDIK. I never really liked the basic college student set up. I still don't. But I kept reading so much praise, I had to try it. I was pleasantly surprised. Nice characters (most of them), nice renders, very well put together, great build up, decent writing. I would probably love it if it were...
I did and I didn't bother to play it. Knowing for certain it will stop abruptly at any moment just kills it for me, even if it has everything I ever wished.
Ren'py. Easy, perfect features out of the box for most vns, wildly known, easily moddable. Unless you're making a game that require other features, I don't see why anyone would pick anyting else.
As most things, I like them if done well. More often than not you can find games that are slow but they're not burning at all, it's just pure stalling. But there's a few that do it right and it's very satisfying.
I don't mind action between harem members, it just doesn't do anything for me if the mc is not involved. I like it very much if he is though. Also no trans or lesbians.
They're inherently risky. Anyone who's not familiar or simply doesn't care too much about the source material probably won't play it. For those who may be interested, setting the mc, tone, plot and so on to everyone's taste is probably impossible.
That being said, they can be as godd as any...
Hard to pick one. But one I like and there's not enough of is the stern and cold, kind of bitchy milf, that needs to be pushed into discovering her long locked down lust and degeneracy.
I obviously don't like it, and have my own opinion on the effectiveness it may have to generate income and retain followers. But otherwise don't really care, it's their place to do whatever they see fit.