Nope. Have Raf. Can confirm he is still slow. I’m leveling him now, and I believe he will be much better than his reception on the forum would indicate. That said, the answer is Kiril, and I don’t think it’s really that close. After almost two years as FTP, Kiril gets as much play as any hero on my roster. I have him at +c20, and I don’t regret it at all. Boril becomes obsolete, at some point, and Raf is really good within his niche, but his niche is not as large as Kiril’s. Kiril is a healer and buffer, and don’t underestimate the utility of him being able to reverse attack down and defense down - two of the most common ailments in the game. He can work as well as a cleanser against heroes who apply those ailments.
There are very few heroes that can bump you from platinum to diamond by themselves, and I really doubt Raf is one of them. I think he’ll be much better on offense than defense, as his skill really takes proper timing to maximize. Also, unless you have the scopes to max Raf, a maxed Kiril will be better than a 3^70 Raf, as mentioned by @Julia above. In fact, in almost every case, a 4^70 epic is better than a 3^70 legendary. That’s even more true with the advent of emblems, since you can emblem a maxed epic, but not a 3^70 legendary.
I know Raf is a shiny HotM, and like I said, I really do think he’s better than he gets credit for, depending on your spending habits. I’m excited about maxing mine, for sure. But as the great (and possibly now retired?) @Gryphonknight advised somewhere on this forum - epics are the backbone of your roster; legendaries are the icing on top. Invest in Kiril; you’ll be glad you did.