> "Dumping the old Windows Mobile platform for Windows Phone was understandable, but the compatibility break between Windows Phone 7 and Windows Phone 8 was really off-putting."

My memory is fuzzy on the specifics but the breaks weren't done just for the fun of it. If I recall correctly, refactoring on a titanic scale on the Windows Phone OS was underway along with the same on Windows itself to both make Windows a componentized OS that would work on anything from a tiny mobile device to a huge server and to synchronize the architecture of WP to Windows. By the time of WP10, as the old joke goes, "the operation was a success but the patient died". It's kind of a pity.