Not a bad ending. There are a couple head-scratcher moments where certain consequences are kind of glossed over or ignored, but I guess you could chalk it up to dramatic license. It had to wrap up some how.
Judging by the content of the final sex scenes, I think it's pretty clear that Leah is the true ending. Her scene had variety and length while the other scenes were very brief in comparison (and for the most part, less distinctly romantic). For several chapters, It's seemed like the Devs didn't really know what to do with Sam and that didn't really change much in the ending. There seemed like there was more romance and purpose with her toward the beginning of the VN to ending up being just a FWB. Also, I'm a little sad that Sandra didn't end getting a romance ending like the other girls. She had enough content and sexual tension through the whole VN that I thought she had main LI vibes, but I guess she wound up being just a sidegirl after all.
Also speaking of side girls, it's a damn shame Tiana didn't get a scene after that big ol booty was teased in the last episode. Missed a golden opportunity for Tiana action in the solo ending.
Overall, I think the endings with each of the girls could have been more even with Leah's scene, but Leah's scene itself was satisfying. The imbalance of the individual endings made it feel a little rushed though.