I have not read all 23 pages, but can anyone tell me what's the most important reason for choosing the M8.
While there are other treads that might be more appropriate for that question than the order and shipping thread there is no one answer. Different people have different reasons for choosing the m8. Some of those reasons might include:
Dual front facing speakers that are well built, and provide excellent sound. The only other phones with such speakers are the other One phones from HTC. If you watch videos or listen to music on your phone (or plan to) this is an excellent reason to choose this phone.
Extending on the well built piece it is one of the highest build quality phones available with some top of the line hardware components, and well refined software programs. The build quality and quality control is some of the best out there. Very few people receive faulty hardware components, stuck pixels, or other defects that are common with other vendors. (There are a lot of people who foolishly blame hardware when then can't figure out a problem, and either return or exchange phones for other phone models or used phones. Don't fall into the same trap. If you encounter problems with a phone - be it this one or some other one- its most likely an app or setting at fault). It is one of the few phones that is without lag switching screens and loading apps swiftly.
Besides being quick due to the powerful hardware components, and well developed software the phone also has excellent battery life. While Verizon strips the phone of its extreme power saving mode the phone still has long battery life. I've (on Verizon) been able to get three days out of the battery without needing to charge while still maintaining speed in it use.
HTC has the advantage program which provides benefits like free screen replacement if it breaks in the first 6 months of ownership. Also as part of the advantage program they promise to provide OS updates for two years from the release date of the phone. The phone came out in mid April, so that means updates for almost all of the two years a person would be on contract with their carrier.
Finally there is the look and feel of the phone. It is one of the better looking phones out right now, and while heavier than some of the other phones out these days it has a nice balance, and doesn't feel heavy during use.
There are many other reasons people choose this phone, and you can find the reasons in other threads, forums, and reviews.