Are silicone keyboards silent?

I take notes in class and at talks on my iPad because 1) there’s no vertical screen interrupting the space between me and the group/professor, and 2) typing on the touch-screen is as silent as it gets, which is important for a non-distracting atmosphere and for making audio recordings of lectures.

But it would be really nice to have more screen space – the built-in iPad keyboard takes up fully half the screen. So I’m looking at bluetooth silicone keyboards (I won’t use the type built into a case because they make the angle too vertical), but I’ve never used one before.

1) Are they as silent as a touchscreen keyboard, or nearly so?
2) Do they work well? Reviews I’ve seen so far say that in many cases they do not pick up keystrokes properly. Is this a problem with bluetooth keyboards in general or with silicone keyboards in general, or just with crappy keyboards in general?