After 6 weeks with the M9 (following 2+ years each with an Incredible and a DNA, both HTC), I am still wowed by HTC phones, looks, build quality and functionality. Customer Support has slipped a bit - my few calls over past years were answered by knowledgeable, helpful staff; but my last call was answered by somebody hard to understand who knew only her name without help from a supervisor - ah, progress! Like the M8, which I skipped because of the damned speakers, the M9 has only two real problems so far:
1. It lacks a lock screen ID (Owner name and contact), requiring that I add text to my lock screen photo. It should have a text overlay to show that, the way phones did in the good ol' days.
2. It has those big speakers that make the phone unnecessarily long. How many of you actually listen to Beethoven's 5th Symphony or watch Star Wars on your cell phone - without earphones? The little mono speaker on the back of my DNA did the job nicely. In fairness, it is impressive that they added mega-speakers and kept the M9 only very slightly longer than the DNA, but I'd much rather lose another quarter inch of length.
On the plus side. HTC did some great things with the M9 (again vs the DNA). The side power button is a great move and much easier to use after you get used to it. The Interruptions utility is a good idea, though I am still getting used to it. The long-press symbols and numbers added to the keyboard are a real time-saver. I have seen much discussion about the camera, which is not an issue for me. I travel with a camera for "real" pictures and use my phone for casual shots, shopping (taking a pic of the 27 weird fluorescent bulbs that we now need), scanning short documents, golf videos of friends' swing idiosyncrasies, and the like. It works just fine for all of those things. The voice to text processing is awesome, too. I now dictate notes, shopping lists and text messages.
There are two other issues that may not be HTC issues: SIM card swaps and non-removable crapware (e.g., Cookie Jam). I travelled to Europe with the M9 and the local SIM cards worked fine, with a couple of minor squawks: calls said they were coming from/going to random countries and the tethering/hot spot did not work in London (ee, formerly Orange and T-Mobile), nor Amsterdam (Vodaphone). The problem arose when I returned home and had to visit a Verizon store for a new SIM card. VZW says that the problem is Android phones do not "reprovision" themselves automatically; meaning that once you add a non-VZW SIM card to your phone, your old VZW SIM card is bricked. I had the very same issue with my DNA, also Verizon. My wife's iPhone 5 had none of those problems; it tethered, hot-spotted and reprovisioned itself when I reinstalled her VZW SIM card. With the dearth of public phones, it is terrily inconvenient to come home and find you cell phone useless. VZW did agree to send me a spare SIM card so that I can at least get reprovisioned on the fly, well, after-the-fly.