I just read the first five volumes of Sukitte Il na yo. From it, I can conclude it's like BGI in the sense it's about maintaining a r/ship instead of forming one, which is where the vast majority of romances be it shojo or seinen, end. Seems a bit more lighthearted than BgI (which had an obvious "dark secret" undertone from the very start regarding Nana, Yano's ex), but it's starting to be serious now.
As for the other shojo, Tonari no Kaibutsu-kun, well can't say I'm interested. I don't exactly have the best experiences with Shojo romcoms... I disliked stuff like Lovely Complex, Special A and Itazura na Kiss. Skip beat was decent though, although it wasn't excellent. Josei romcoms tend to be a lot better however - Nodame Cantabile, Princess Jellyfish, Paradise Kiss to an extent (though it wasn't pure comedy).
But yeh, I come from a shojo manga background, so I do have a natural bias for the shojo drama genre and BgI was the absolute best for me
