Thanks David, actually I had seen all of those clips before and more besides (back when I went out scouring youtube for examples of Blender hair in animation) and those same clips are exactly what I based my prior opinion on.  It's funny how we can both look at the same clips and come to such different opinions, but that's the nature of subjectivity I suppose.  :)    Apples to apples, only 2 of those links:

https://www.youtube.com/watch?v=XzGwkQRpOmQ

https://www.youtube.com/watch?v=H9v1IHo1R1o

Are actual animations that someone (like me) probably whipped up in Blender on their own, trying to test settings and get a realistic human hair behaving with a character moving.  They aren't horrible, and I can see there might be room for potential, but compare it with one of my first tests with Carrara:

https://www.youtube.com/watch?v=wsz65nEkq5U

I'm not an expert or a genius (far from it), if anything I'm kind of an idiot, and if a stumbling newbie to dynamic hair (I've played with Carrara for several years now but never ever animated dynamic hair until about 3 weeks ago) can come up with something like that off the bat, then I think that speaks to how easy/quick it is to get a good simulation of human-style dynamic hair in Carrara.

I scoured youtube looking for other users of Blender and their test sequences and couldn't find anything that much better than the first 2 clips you posted.  My first thought is either there's some sort of limitation in the dynamics of Blender that makes realistic human hair very difficult, or (perhaps much more likely) users just haven't yet figured out the most realistic settings to use.  You know what though?  I also did youtube searches on 3ds, Modo, Maya, Lightwave, Houdini and C4D.  Found some pretty good ones for C4d and Lightwave, and a few that were decent for Maya, but I also found lots of ones that were not so great to very poor, even with the big name/price software.

I had watched the other clips you posted too, but most are tutorials on how to create realistic hairstyles in Blender and don't include any particular animations of it reacting to dynamic forces (I watched them about 2 weeks ago when I was thinking 'it can't be this easy' after my first experiments with Carrara hair, and I was looking around to see what else was out there).  The other links were for a cartoon-stylized short (Big Buck Bunny) which has no human style hair (though I do love the movie, don't get me wrong) and Sintel, which is in a category of it's own.

 Now as fur and grass, Blender hair looks and behaves great in animations (as in Big Buck Bunny), and obviously neither Big Buck nor Sintel were aiming at doing a realistic style of hair, so even though they had a big budget and large production team for Sintel, just because it doesn't look like realistic human hair doesn't mean there's anything intrinsically inferior about Blender's hair sim (it's not supposed to look realistic in that show, but instead is supposed to match the stylization of the rest of characters in Sintel) and of all the animations I've seen Sintel is the one where it looks like the dynamics of the way it moves in reaction to scene forces (wind, character movement) that there could indeed be a good dynamic hair physics engine buried deep down (though it often looks more like cloth movement to my eye than strand movement, but leaving that aside).  On the other hand, it's very difficult to know when you're talking about a production with a big team working together about what went into it, so I'll just reserve judgment altogether, except to say I don't think anyone should hold it's lack of hair realism against it, as that was never the point and would have looked out of place anyway.

 My general opinion is that it could be possible that Blender may be able to produce realistic dynamic human hair in animation, but I don't think the users have 'cracked the code' yet of what settings to use to make that happen.   I should never say 'can't be done' because I've seen that label misapplied too many times to other software (as for example it often is with Carrara).

Blender has Cycles, an outstanding unbiased render engine.  I'm even more jealous that there is a plugin for TheaRender, my personal absolute favorite unbiased renderer of all time.  Currently if I want to render in Thea I have to export to .obj and import into Thea, retexturing once it's there.  I would kill for a plugin for Carrara to Thea but sadly it doesn't exist yet.  In fact, if Blender suddenly got native daz/poser support tomorrow, that along might enough to make me flip over to making Blender my goto app, even though I find the UI in Carrara waaaay waaay more easy and natural to use (but then again I'm already used to Carrara and comfortable with it's UI).

On the other hand, Carrara does have plugins for Lux (Luxus and now Luxcore), and Octane, so it's not like there aren't unbiased render options with Carrara too.  Nowadays nearly everything has unbiased render options.  Iclone even has Indigo, for example.  Not sure if Vue has any... but I'm wandering from the topic.

I sometimes wonder if I could go back in time to when I started dabbling with this hobby, would I tell myself to go with Carrara?  I certainly am no fan of Daz, and have 0% faith in their development.  I do think there will be a Carrara 9, but I'm just about certain it will all be fixes to use Genesis2 content more easily and nothing much more substantial than that.  But for what I need, I think Carrara as it is does just about everything already, so even though there's little to no real development, I'm still good with Carrara as is, and I'd probably tell my past self 'go for Carrara, you won't be unhappy'.

Although if Blender got native use of daz/poser stuff, I just might have to flip to using it as my main app instead of simply an app that I use for a few things when needed.  Oh how I wish there were a Thea plugin for Carrara.  I might have to study up on programming languages and create it myself  (after all, I once slept in a holiday inn express  :)  )