The biggest change from the Gemma to the Trinket is a more square-like layout for the snaps. This is shaped more similarly to the majority of the official components.
Also of note is the Trinket has mounting holes (albeit teeny tiny ones) which means I can bolt the board on instead of gluing it down.
Those of you familiar with Trinkets will notice that I haven't exposed all of the pins on the trinket to snaps. This choice was largely to limit the final size of the plate. Since I decided to expose only a subset of the pins, I had to decide which ones it would be. In the end I couldn't make up my mind all the way so I put female header on my trinket and plug into it with wires coming off of the snaps. This way it is reconfigurable.