We bought one of these and used it every day. That is until a single piece in the base simply fell off (no crack, just a chip came off when full of freshly hot tea) and made a right mess. We spoke to B&B and they offered a replacement because of the quality issue. I hoped it was a one off.
This weekend, when again full of fresh hot tea, a single chip of glass detached (see image of the, admittedly dirty, cup after being emptied) which has made the handle unsafe to use.
At this point I'm convinced the manufacture of these glass tea mugs is inadequate. We've gone through two of these now in less than a year. Apparently they can't handle hot tea, which is a bit of a design flaw.
Absolutely can't recommend this product until it's been actively investigated by the company as to the build issue of the glass when under daily hot temperatures (can't believe I've even written that!)