I have the same build and my start menu is transparent too, well only just, I can barely see anything behind it and I'm on the same build as you so I don't understand how the tiles are getting in the way. If anything the transparency I have on my newly downloaded 10041 build could do with more transparency lol. Cant even make out icons except a vague shape. In terms of bugs I had to put in 1 script to get mail and people, calendar to work. Live tiles don't update to well sometimes but then again it is a preview build and I am supposed to be on the fast lane so bugs are warned and expected.
Cortana works great cant wait till full intermigration. Personally I haven't found any more bugs but I'm using this pc as my daily go to pc and I'm not looking hard for them, I'm just using the machine the same way I usually do. Wish they'd change the icons I'm not a big fan.
I do like the big square setting icon I sometimes see in the top that might be a design to use across the board. I am surprised how well it works for a developer preview.
Biting the hand that feeds IT
