I also had a spiegen t-slim glass one and it was terrible. It started to chip away from one corner after a couple days of usease and it's definately because it's not rounded in the corners, it's sharp so it was bound to happen. A real piece of trash imho. They wanted to make it extremely slim but it's way too fragile and britle.
On the contrary the Brando one is absolutely wonderfull, rounded, very strong, realy good olephobic coating and realy premium glass feel to the touch. It adds a little to the screen ofc but makes the phone even look more premium. Also, it's not a tight fit to the edges of the phone so most cases will do just fine even with the added glass on the screen. (i use a spiegen ultra case and it's like the added glass is not there at all)
I would definately recomend this glass, just be warned that for people who don't use any kind of bumber or case, it does add a little bit on the screen so it does very very very slightly raise the glass over the edges of the phone if you see it sideways, it's very negligeable but it's there. The advantages outweight that only and slight disadvantage for some people who like the xperia Z "pure and raw".
