Arggh. Now I remember, this kind of cryptic product status was part of what settled me on Emvoice, even after I figured out how to download the free Synth V voices and played with it a bit. The idea of selling "pre-release" software is a contradiction, unless we're talking about black market leaks. I do want Synth V, but I think I'll wait until Synth V decides it's really for sale before investing the time in learning it.
It's not that they're selling beta software, it's that the software is being sold before it's available - that it, "pre-release" means that you're buying something before it's been released.
It's pretty common in the virtual instrument world to do this, as it gives developers some cash to work with, and typically rewards buyers with a modest discount.
In this case, they're also rewarding early adopters with copies of the software before it's generally available. That's not a big incentive for me, but apparently it's enough of a driver that they've made it a point of there pre-sales campaign.
If that doesn't float your boat, that's fine. I've also purchased the "pre-release" of Anri and SOLARIA, but that's just because I'll get them anyway, and who knows if I'll have the spare cash available when they are released? Plus, I want to support the development of more/better SynthV voicebanks.
Your preference is to pay for things when they're ready, and that's sensible. Plus, you've already got a pair of voices with Emvoice, so you're only only talking about adding yet another synthetic vocalist to your stable of singers.