Which is riskier?
7.1 betas. Isn't that obvious? Where is the risk in staying on 7.0.4 - if we are discussing jailbreak here.
And no, devs won't update to support 7.1 when it comes out. Think about it - what's the reason they don't support the beta now? Because they can't test it. When 7.1 is officially out, how can they test their tweak on it when it's not jailbroken?
No lightning hdmi out on the betas is an easy 'No chance' for me. But even without that, the lack of support from devs and *regardless of how much 'proof' we have* the risk that apple still disables the beta(s) just isn't worth the effort imo.
And to answer your updated title. I'm sticking with 7.0.4 - for the reasons above and I have used 7.1 b2, both jailbroken and not...I have noticed some crashing in safari on 7.0.4 but aside from that I haven't noticed any difference. Maybe animations are better, I don't know, I use reduce motion + fast animations so I hardly have any time between switching into an app, basically none of this zooming/fading in and out stuff...