Sandboxes with first person point and click exploration with no grind, no pointless gameplay mechanics and no pointless character stats(other than perhaps money) seem to be what works best for me (example: milfy city, area69) . Padding out the game with pointless random combat encounters straight out of dragon quest (Milftoon Adventures) and random puzzles out of windows 95 desktop adventure games (NLT Media) serves absolutely no erotic purpose, only perhaps a marketing one by bloating the game length or advertised amount of content.
Prefer being able to select which location to visit and guide the exploration and choose which characters I talk to in whichever order. It gives a sense of being there and agency that feels missing from a lot of VNs that often are also too light on dialog or roleplaying choices.
VN's definitely, but if the sandbox is well implemented and not insanely grindy and makes me look at a walkthrough every 2 minutes to know what to do then I don't mind it.
Neither?
VN= Got tired of choice based play style after a dozen or so.
Sandbox= ends up kinda the same, just hunting for the trigger or whatnot to get the event/cg/etc.
I don't like grindy sandboxes, but at least they give you some agency. I don't even consider VNs as games tbh. Any VN could have been a webcomic. "Choice" in most of these games boils down to "do you wanna watch this h-scene or nah?" or "do you want the next scene to be rough or vanilla?"
If a game has sandbox and looks like it's sandbox, then I always download them. VNs become boring for me real fast as it's just reading and clicking once or twice. Sandbox's feel more hands on and I'm not forced to interact with characters I don't like.
While I don't tend to actually like most sandboxes, I do prefer the idea of them. First and still favorite adult game was Aurelia, and it spoiled my for quality of sandbox.
Somewhere in the middle. I don't like sandbox games without any progression and story, nor do i like VNs with no grind and very little choice or gameplay. I prefer a good RPGM game with a nice story and some free roam to replay some scenes and maybe unlock some stuff along the way.