I stick to Ren'Py most of the time because it's super familiar and player-friendly. I can save whenever, rollback if a choice goes sideways (especially on replays when I'm hunting gallery unlocks and don't remember every dialogue branch), and text-skip makes grinding through known content painless. Nothing kills my vibe faster than a Ren'Py game that suddenly locks rollback after a big choice with zero warning—just "lol no backsies."
That said, I do play non-Ren'Py stuff if it's worth it. Femboy Futa House is a great example—I love the characters, Lucy doesn't make you jump through endless hoops for action, and it's fun overall. But replaying is a hassle without easy rollback/skip, so it mostly holds me over until something like Haunted by Femboy drops (demo's solid, full release can't come soon enough).
Unity/Unreal games do eat more resources, but the bigger downside for me is they're often built with WASD/mouse-look or interactive controls that make one-handed play a pain—defeating the whole point sometimes. Ren'Py nails it: pure keyboard/mouse basics, no fumbling required, which is way better for... relaxed sessions. Modding is also king in Ren'Py—slapping in an incest patch or quick name/relation tweak is just dropping an edited .rpy file. I enjoy some straight-up incest-themed stories, but tons of games water it down with "step-" or "roommate" labels that don't hit the same—Ren'Py lets the community fix that in minutes, while non-Ren'Py mods are usually way more involved (if they exist at all).
RPGMaker gets slept on IMO. Claire's Quest and Melty's Quest are favorites of mine, and there are plenty more solid ones out there. The downside is they usually require way more grinding/exploration before the lewd scenes kick in, so I tend to skip them unless the premise hooks me hard.
Curious what others think—any non-Ren'Py gems that changed your mind?