I took a look at their Kickstarter page and those things look pretty nice. I really like the fact that they're vertically oriented, since most dividers out there are horizontal.
In the process of making my own dividers I came across lots of things that I liked and didn't like about dividers -- these are made of plastic which is a big plus.
On the other hand, there is one thing about these dividers that I think could be an issue, and is something I ran into as well. Having them be opaque and square means you have to be looking at them almost vertically to see the labels, which makes them difficult to read, especially if you're looking over a lot of cards for the one you want. I've played a LOT of IRL Dominion and can speak from experience here.
I had two different solutions to this particular issue, both of which solved that problem:
You can make the dividers tabbed so that there's more space in between, or
you can make the dividers transparent. Both of these have been effective for me, though they require the dividers to be reversible and probably more expensive.
But, you know, they would actually be usable.
This is still in Kickstarter, so maybe there's a chance they're still open to suggestions like this since they don't seem to have manufactured them all yet, but my takeaway from reading that page is that they wouldn't really be open to making larger changes like this, especially from someone who isn't going to be buying their dividers (I recently spent a LOT of time making my new PlexiGlas™ dividers and I'm happy with them).
Do you think they would be open to listening to my feedback at this point? I'm not sure where to go from here or if I should just stay out of it.
EDIT: I sent a message and he responded very quickly. He said that he asked people about it and they said they would rather keep the price down.