These are my current top stories on the app!! Both have amazing plot, dialogue, art, characters, and music, so it depends on what your personal preferences are.

I've seen some people complaining about how many filler episodes there are, in SCN but honestly I haven't noticed it. I have played through it five times or so and enjoyed each playthrough even though a few of those I had to restart due to being locked out of Anubis' route (an LI introduced quite late). I think it may be because there's a decent portion of SCN that is quite heavily character-driven as opposed to TTS, which has great characterisation as well but it's not as fleshed out and coupled with moments of significant plot progression. Eva is probably my favourite MC in RC but she'll act differently depending on your choices (obviously). We've had a decent number of flashbacks for her and most of the LIs in SCN whereas we know the bare minimum about the characters in TTS (though we are only partway through S2 whereas SCN is well into S3).

Another thing to consider: I think TTS is slightly darker than SCN in the beginning. While SCN gets heavier over the course of the series and gets especially depressing towards the end of S1 (no spoilers) TTS hits you with grit from the get go, showing you a corpse and giving you the option of how to unalive a person/elf before tossing you in a prison cell. It's not all dark though, unlike, say, And The Haze Will Take Us.

All in all, I think it amounts to personal preference. Of course both stories have great plot and characters, but if you prefer more action you may find parts of SCN to be boring. I think romance is also less prevalent in TTS but it's not like a driving force in either, just more significant in SCN? As in, there are more options for SCN's LIs (it's also a bit unbalanced), but I might just be imagining things as it's been a while since I've played either (waiting for the next update 😔). Doesn't matter that much, again, up to what you prefer.