I should update this thread and say that I did get a Matias Mini Quiet Pro and am quite happy with it. It's definitely a keeper, even if it's not a favorite among my other keyboards.
The tactility is very pronounced, has a more coarse feel in it's resistance bump than Cherry, with the collapsing of the resistance at the top of the press (which is preferable for some people), and it's about as quiet as a standard rubber dome keyboard. According to the VP of Matias, the tactility between the quiet and the clicky Matias switches are pretty much the same, with the only difference being the sound, so if you love tactile switches but don't like the noise, the Matias quiet switch is one of the best choices available right now.
I would rate it as more tactile than Cherry blue and Topre 55g, and slightly more quiet than non-silenced Topre, but not as quiet as Type-S RealForce Topre. The coarser tactile bump is part of what makes it feel more tactile, and it's a subjective thing--some will not like it, and some will prefer it to snappy tactile bumps. If I had to choose, I'd prefer snappy and crisp tactile bump (which is why I always liked Cherry blue), but I don't hate the coarse feel of the Matias either--I'm kind of neutral about it.
The Matias is different enough from Cherry MX that I would never sell mine, since my overall approach to keyboards right now is to keep at least one keyboard in each major switch category, and the Matias quiet switch fulfills the ALPS category for me. I'm a little annoyed by having to use Fn layer for the Home/End keys, since there's still space right there to fit those keys in but Matias chose to put them on Fn layer (using Page Up/Down), but it's not quite a deal-breaker.