iPhone 5s or HTC One: Help Me Decide!

I'll be in the US at the end of September and I've decided to make the switch to either an HTC One or an iPhone 5s. Never have i agonized so much over what should be a pretty simple decision, so I'm turning to you, Apple Core, to help me out.

I don't want this to turn into an iOS vs. Android thing, so if you could please focus on the pros and cons of the iPhone 5s on its own merits, that would be great. I've put up another thread in the Android Army forum to focus on the pros and cons of the HTC One so if you have any thoughts to contribute on that, please do so in that thread. I will be buying either phone outright and unlocked, so price/contract/carrier discussion/etc isn't really a concern - both are similarly priced off contract.

Background

I've got a Nokia Lumia 920 (dat Cyan) that I really do love for the most part. This phone is my daily driver. I have always carried (and still carry) a second phone (either iPhone 4 or 4S) with an iPad SIM card/plan in it, even back in my beloved BlackBerry days, for the app ecosystem. However, I am getting a little tired of carrying two phones so I'm looking to consolidate.

Reasons why I am interested in the iPhone 5s:

App Ecosystem - I own an iPhone and an iPad so I'm comfortable and familiar with iOS apps and I've already got a stable of great apps at my disposal that I could reload from iCloud and be up and running right away.

After-Sales Support - There are Apple stores everywhere around me (I'm in Canada), so I would be able to get it serviced very easily even buying the phone from the US. Also, Apple has a phenomenal track record with OS updates and supporting a device for at least a few generations.

Camera - Coming from a Lumia 920 I'm already used to a pretty fantastic camera, and from what I've seen of the 5s, it won't disappoint in that area when it comes to photo-taking. I'm also really intrigued by the larger pixels and the extra photo processing exclusive to the 5s.

Battery - iPhones have always treated me very well with regards to battery life, and the 5s is supposed to be even better in this area.

Reasons why I am hesitant about the iPhone 5s:

Sound - I listen to a ton of podcasts and/or watch a bunch of videos just before falling asleep (using the phone's speakers - I don't like falling asleep with headphones in). Previous iPhones have a fairly average mono speaker which is pretty meh. Does anyone know if the 5s will have any improvement in this area? (Doesn't look like it from what I've seen)

Screen - The screen is not as nice as the HTC One and is a little small. I'm willing to make that trade-off given that it feels much more comfortable in the hand, but the fact remains that while the screen is good, it's not best-in-class.

Camera - The Lumia 920's camera is fantastic, both for photo and video. Photos taken with iPhones look equally great (better in many cases). But specifically for video recording, the Lumia's OIS is out of this world. It makes videos look like they were shot on a tripod or with a steadycam. Also, audio recorded with my Lumia 920 at a concert is so crystal clear it sounds almost like it was taken straight from the sound board. I've compared the same video shot with my Lumia 920 and an iPhone 5 and the iPhone is so blown out, distorted and useless, while the 920 sounds like CD quality audio. Does anyone know if the 5s has made any improvements to the mic used for video recording? That's something I'm very worried about.

Bluetooth - My Lumia 920 has the best in-car Bluetooth implementation I've ever seen. It pushes track information and album art from all my apps (Rdio, podcasts, etc) to my car's dash display (something the iPhone also does), but also integrates seamlessly for reading text messages and dictating them (something the iPhone does in a much more limited way based on my personal testing). I'm worried about how the iPhone 5s will handle this. Does anyone have any experience with iPhone 5 and in-car Bluetooth? It left a lot to be desired when I last tested it with my 4S.

If anyone has any advice or comments they could share regarding their iPhone experience or can comment on any of the things I mentioned above, that would be great!