Came off w/o a hitch... but I would not try this if you don't consider yourself fairly handy. The guide was super helpful!!!
...took my time and zoomed in on pictures, read the comments when I was stuck. Took a break before reassembly. Reconnecting the small, layered connectors near the top took the most trial and error for me. A jewelers magnifying headpiece could have been helpful there...will buy a cheap one if I do this again...
Do this after your kids are in bed! Use good lighting and leave plenty of space to lay out parts and screws in their correct layouts so you remember how they go back in. User comments in the guide were helpful...particularly one about transferring over, from old to new assembly, a little white sticker up around the camera assembly. I believe that's on the thermal sensor. Anyway, that sticker came off and transferred with no problems. Phone is well designed, so most things snap/pop into place fairly easily when they are lined up correctly. I would say, be gentle- if you have to force it, look closely or take a step back and see what isn't right.