I’m a big fan of Thumbs-ups on my Leicas. On both M9s that I own, the original Thumbs-up are almost permanently attached. I moved one of these to my new M240 when I bought it, but there is one big disadvantage with the current design: it leaves the EVF port useless and that’s inconvenient. If there is enough time, switching between the thumbs-up and EVF is not a problem, but on a wedding, there is never enough time, so I tend to use the EVF only on non-wedding occasions.
I mounted the Thumbie a few hours ago and it was very easy. I’ll keep you posted. A proper review will follow.