I purchased an AVIC8100 NEX and installed it in my Mazda CX-5 early this past weekend. Here are some initial thoughts:
First, and this drives me insane, the TTS voice for the built in navigation sucks. Badly. Not only does it mispronounce nearly every street name, but it also seems to have a very hard time with abbreviations. For example, when approaching "exit 10" for "I-76 east bound", what it says is "Exit 10 dot I seventy six exabyte" (I'm guessing that the TTS thinks "EB" is an abbreviation for "Exabyte" I have no idea why it has to say "dot" after exit numbers. As well, it's amusing to hear state road names. Instead of "P A number", or even "Pennsylvania number", I get "Pa number" ("pa" being pronounced like someone might call their father.)
I've encountered the issues with using an older iPod (5th gen) and not resuming. That should be resolved with an iPod classic (160GB), however. I hope.
Aha radio sucked the last time I tried it (a few years ago) and still sucks. Pandora isn't much better (simply because they REFUSE to allow a way to block "live" songs and I really don't want to listen to live recordings in my car.) I can't blame this on Pioneer - at least they have the options for people who want to use them. I could wish that they had MORE similar options (such as iHeartRadio.)
AVICSYNC: This is comical: All over the UI it reminds me that I'd get more and/or better features if I connect my phone (with AVICSYNC), but the AVICSYNC app doesn't exist (for either android or iPhone.) Sad.
Other than the TTS, the built in nav is okay. It's not as good as the current generations of either tomtom or garmin, but reminds me garmin units when portable GPS's were a new thing. These are mostly mapping and calculation issues (such as not choosing the best route, being completely wrong on house numbers, etc.)
Playing music from SD or USB works fine, but the lack of playlist support from these devices is a silly shortcoming. This is supposed to be a top of the line HU!
The Screen: I really like the capacitive screen - unless the sun is out. It seems that they could have had a capacitive screen with a matte (or frosted) screen surface to reduce the massive glare. Sure, it might cost a couple dollars more, but isn't this the top of the line unit for Pioneer? Fortunately, this should be easily resolved with some kind of film on the screen. Then I should have the best of both worlds.
Reverse camera, HD Radio, and bluetooth audio all seem to work as expected. I like being able to turn on the reverse camera without putting the car into reverse. It really amuses my son to watch that while I'm driving.
I don't have appradio, mirrorlink, carplay, etc. The only other phone connectivity option I have is Android Auto...
Android Auto:
I have a nexus 6, so android auto (AA) works for me. Keep in mind that android auto is a google product (not a pioneer product), so any issues are likely issues from Google, and not from Pioneer. That being said, the integration seems reasonable. The device only allows music from AA or the HU (not both) and only allows Nav from AA or the HU (not both), and the respective audio comes over regardless of what mode the radio is currently in (so AA navigation speaks while listening to an iPod, for example.)
That being said, AA is most definitely not a refined product at this point. There are issues, and I hope that google resolves them soon.
For example: If the HU is talking to the phone via BT (USB not connected), and then I turn off the car, plug in the USB, and restart the car - some of the time, AA won't start properly, first requiring me to answer some prompts from Google's Play Music. (prompts that I've answered many times over... use standard, accept licensing, etc.) The voice recognition doesn't work without an internet connection. (It should, as I have offline voice recognition enabled.) There are others.
Overall, I like the unit. I'll like it more once I get my ipod classic (160GB) working on it. I'd be thrilled if the built in nav TTS was fixed, but I'm not holding my breath for that. Being that I live in a rural area, I drive through many areas with no data service, so Android Auto can't serve as my only nav.