They both sound like pains in the ass, though for different reasons.
Alpha’s emotional coldness and avoidance behavior sounds like she’s got some psychological issues that will probably cause no end of drama sooner or later. She’s probably interesting to talk to, and being intellectually challenged is a plus, but her instability will almost inevitably lead to arguments. Plus, she’s got a good chance of being bad in bed because she’s not comfortable with intimacy. If I’m wrong about that and she’s got no real hang-ups in the bedroom — if she’s into fucking and hot monkey sex — then that might be a bit different for the short term. Never being able to let your guard down and just relax with her would probably get on my nerves after a while, though. Hell, even though I’m a dude, I at least like a little bit of cuddling after sex. That’s not likely to be an option with Alpha. Datable, but no long-term potential.
Beta is a co-dependent emotional basketcase in the making, and probably boring. Like Fretful Porpentine said, I’d probably be bored with her and feeling guilty about it. Jealousy of an outside relationship is pretty much guaranteed with someone who is “supportive” like this. In the event that she’s actually nice enough and open enough to understand the need for the kind of social relationship she can’t provide, then it might work out, but the chances of a screwed up love-triangle, growing disinterest on my part, or something else going wrong are pretty high. She’s probably got the opposite problem from Alpha when it comes to naked happy fun time; all Lifetime Channel emotional connection “making love” all the time, no down-and-dirty screwing allowed. I’ve dated a couple of girls like this for a short time, but it’s never gone for long because uninteresting people aren’t fun to be around.
If I were single now, I wouldn’t be with either one for long. I’m older, wiser, and a little bit nicer than I used to be. In my twenties, I probably would have tried dating both at the same time and eventually gotten caught, or dumped one or the other after I got bored or fed up with her bullshit.
If I were forced to choose one of them for a spouse, I’d probably choose Beta just because she’d be a better wife and mother, and from a completely selfish point of view would be easier to manage. Like someone else pointed out, it’s easier to get someone to expand their horizons a little than to get someone to learn empathy, so it’s even possible that she could be less boring in the future. My tolerance for drama is a lot lower than it used to be, and Alpha seems like the kind of woman who would end up destroying a marriage and enjoy walking away with half of whatever we managed to build together. She’d be a bitch of an ex-wife, and a shitty mother while she was around.
My wife is genuinely nice and supportive, and is also at least as smart as me. She has different interests, but we’ve got enough overlap that we do have things we can enjoy together. She has slightly sappier taste in arts and media (go figure, she is a woman after all) but is almost as critical of badly-done books or movies as I am. She’s not afraid to tell me when I’m full of shit, but isn’t actively disparaging. In other words, she’s a good match for me, which is why I married her.