Ease of Play
I went with Savage Worlds because I played it a lot years ago and generally think it's a fun game; at one point I probably played more Savage Worlds than D&D, so there was a layer of familiarity there and it didn't present a big "re-learning curve." Savage Worlds's basic rules also seem pretty easy for players to pick up. Although most of my players in this game had no previous experience with Savage Worlds, they got the basics down really fast.
On my end, as the person running the game, Savage Worlds has a lot of stuff I get to play with. By stuff I mean: enemies, powers, and bolt-on widgets to enhance the game. Especially taking the Fantasy and Horror Companions into account, I don't have to spend time kit-bashing cool stuff for the game. I can instead focus on the adventures and overall campaign, as is my preference.
Krevborna and "Genre"
Savage Worlds felt like a good fit for Krevborna because despite being billed as a "generic" system, it's actually quite geared toward Big Pulp Action, which is mostly what Krevborna is about. Krevborna is a Gothic setting, but the setting focuses more on the swashbuckling, monster hunting end of the Gothic rather than the quiet, contemplative Gothic. Krevborna has always been more Brotherhood of the Wolf than Wuthering Heights, so mechanics such as the Wild Die, exploding rolls, and Bennies it fits the intended experience pretty well.
Character Possibilities
In many ways, this is the facet most interesting to me: one immediately obvious difference between running the Krevborna setting with Savage Worlds instead of D&D is that Savage Worlds opens up a lot of character concepts that fit the setting, but don't really don't fit D&D's class-based system. For example, two of the the characters in the campaign are a noblewoman-turned-prioress and an anatomist, neither of which map easily to a D&D class.
Catarina, the mysteriously widowed noblewoman, has a skillset focused on occult lore, persuasion, and shooting a pistol; I suppose she could be a rogue in D&D terms, but thievery is not her bag. Since she's now the prioress of a convent devoted to a primordial sea entity, cleric or warlock might seem plausible, but she wields no magical powers. (And I'm pretty sure her player isn't too interesting in dealing with the extra bookkeeping that comes with rpg magic systems.) Simply put, I just don't think Catarina exists in D&D, which is a shame because she's a great character!
Pendleton, the rogue anatomist, feels even less like a D&D character. Again, great character! But the mechanics of D&D don't really have a place for a non-magical medical man. (He has since begun to explore alchemy, but he had no magical abilities at the start of the campaign.) It's worth nothing that both Pendleton's and Catarina's "archetypes" are entirely natural to the notion of Gothic fantasy, but they remain a bit alien to D&D's vision of standard fantasy.
As the necromancer in the party, Raoul corresponds more cleanly to a D&D class, but I think Savage Worlds does a better job on delivery the fantasy of being a necromancer. D&D might make you wait until you gain a few levels to get a subclass that really brings the flavor you had in mind to life, but in Savage Worlds it's easier to get the kind of character you have in mind right away.
Also, to cap it off, I think we've been enjoying the more organic character growth possible when the character exist outside of a class-based system. Catarina's player has been able to focus on the elements of her character that interest her, while Pendleton's player has been able to branch out and add a whole new toolkit (the aforementioned alchemy) to his character. Raoul's player has gotten to pick the type and flavor of his necromancy; man, he's gonna love being able to summon a giant skeleton going forward.