Been lurking here for a while, but gonna pitch in on this topic as I bit the bullet back in June and bought and installed the Alpine i902 (Not the X902, didn't see value in the +$1000 extra cost for Nav when its got AAuto/Carplay anyway)
First up, if you're doing the install yourself, be aware the included in instructions are a bit crap, the included wiring diagram is for the generic 902 head unit, not the VF wiring kit. Some parts are missing from the parts list and the install guide entirely, and some sections are vague. "Simply route the USB & HDMI cable through the centre console" becomes an entire morning of swearing and lost bolts.
(Also the VF wiring kit in mine was missing a part of the grounding wire so doubletriple check it all before tearing things apart)
Nav in the HUD or the screen in the cluster does not work. All guidance is on the Alpine screen or voice only. If you had OEM Nav, the cluster screen will show the option for Navigation, but it never changes.
The Bad
The super shiny Piano Black finish is a fingerprint magnet, as is the screen. Need to see if I can find some sort of anti-fingerprint screen protector.
The screen is
very poor when under full sun. Fingerprints and a mostly black interface theme make everything hard to see.
It uses the headlights to determine if Google Maps should be in Day or Night mode. If you have your headlights on Auto, there's a delay before they turn on, then there's another delay before the maps UI changes. If all you did was pass under a bridge, then its a good couple seconds before the map flicks to dark mode, then back again. (Maybe specific to Android Auto? You can force it to not do this and always be day or night mode )
Rear-view camera screen is not great, takes a while to cut out when moving forward again, has reversing distance lines but they do not move with the steering angle.
The Good
It's not MyLink. It's fast and very responsive. AAuto/Carplay with up to date maps and live traffic is A+
When its not covered in fingerprints it looks really tidy, like its meant to be there.
There is a ton of audio control options, I still have the standard speakers and it can get a very decent sound out of them. It uses the OEM microphone for voice control and phone calls too so you won't need to stick a dodgy mic somewhere ugly.
Full volume control over system noises like chimes, bingbongs and indicator ticks.
Is it worth $2000+ dollars? Eeeehh...debatable, depends on your feelings about money. It is
definitely a huge improvement over stock though.
And some bonus pictures.