I would vote for the first Expansion Soldier's of Fortune becase not only do they play pretty well themselves as a team of four but each of those new characters can enhance characters from the CoreSet in a straightforward way.
I would agree Soldier's of Fortune is a solid expansion and the characters can easily be played as a team. However, had the most fun with the Chemical Brothers so far. :D
I personally love the Human Fate box a lot. Dart is pretty cool, an opponent of mine uses Eclypse so well, Bixie is so friggin fast even if one wouldn't think so and so hard to pin down and Prysm is the annoying bane of all!
As much as I'd like to recommend SoF, I'm gonna have to throw down a vote for Human Fate as well. Just because they are effectively parallels or variants of some core box characters, allowing for more interesting and varied drafts. Definitely grab SoF as the next purchase, though.
I am also on the Human Fate train. Prysm is versatile, Bixie's design is exciting and interesting, Eclypse is not only mysterious but plays really intuitively and I haven't given Dart a go yet but I will!
Thanks! So, it seems like a tie between SoF and Human Fate. Funny enough, from the miniatures point of view, I liked Smoke and Mirrors. So, the choice remains difficult. Maybe the warcor,s advice (roadrunner) will break the tie. ;-)
Don't be afraid to pick up Smoke and Mirrors, it's also got two super competitive choices (Mendoza and Cozmo) a frightening striker (Murtair) and an interesting controller.
I agree with @AdmiralJCJF. Even if they are not the most balanced option to explore different playstyles*, they are really strong in any team you put them. If you really like that box, then it's the best box for you because it's the one you are going to get the most fun. * You can see how they are more prone to close quarter combat than ranged, and how Taowu is more denial than other types of control like displacers or debuffers.
Human fate too. Prysm is very powerful, dart cool, Eclipse very interesting, and Bixie an alternative to Gata. I almost never play the characters of SoF, I'm not a fan of them. But every expansion is very interesting anyway
Human Fate because Bixie is love, Bixie is life. Real answer: It's between Human Fate and Soldiers of Fortune for expanding from the core set, they have a good variety of readily playable characters who tend not to require overly intense combos or synergies to work. I think the Bahadurs are also a great one, but I havent played with them enough yet.