This episode was fine, but it didn't have the same charm that the first 2 seasons had. I think I like the show the most when each episode is a self contained mystery....and no super spy Mary. I have never been a fan of Mary (there isn't room on the show for another super intelligent character), so I wasn't very interested in the USB drive stuff or her backstory. However, I did think her death was pretty emotional.
What's up with John and E? I don't think he is actually cheating, Sherlock would know if that was the case.
Some other complaints.
Why did Sherlock meet the robber alone for the 6th bust? The cops should have been in there to help.
Sherlock can not hold his own with a trained assassin
This assassin hid a USB drive while in the country of Georgia and it just so happens to end up in the same city where Mary is now living?
In case you miss it, way after the credits it goes back to Mary's recording and she says "Go to hell Sherlock"