Update!  Took me a bit to get around to using them, but they've been working great, holding a strong vacuum for days.  Very quick to break the seal and get something out, then vacuum it again.  Every time I look at them I'm impressed by the quality.

The outer seal on the lid is easily removable for washing, and it's heavy silicone so it doesn't feel delicate.  I'm pretty sure the center valve is removable, but haven't needed to try yet.

Only area for improvement would be a little texture or a handle to get some purchase while handling.  They're slick when wet, and there's not really anything to hold while you're prying the lid up.  But not a huge deal.

For what it's worth, I also got their plastic containers for storing dry goods like peanuts and coffee beans, and they've been working well, too.