[Xiaomi Mi A2 / 6X Guides, News, & Discussion] Alecossy:
Disclaimer and Obligatory Background: I'm posting this here because the Discussions section seems the most appropriate one for this post. Mods are welcome to move/relocate the post if they see fit. I work in PR (Marketing/Social Media/Content Creation) and spend most of my days on the phone. Therefore, I consider myself a heavy user. You should read the following review with that in mind.

I've been using MIUI 10 (10.2.2.0 EU) for about three weeks now as my daily driver. The mod is a decent attempt by the MIUI team to bring MIUI 10 to the A2/6X but not the best out there considering the 6X should run on MIUI to begin with. Keep in mind that MIUI 10 is still under development and things may change at a moment's notice. This account of my experience is only valid at the time of writing and I won't consider myself responsible of what you do with your phone after you've read it. Now that we're good with all of that, let's take a look at what works and what I think would benefit from a bit more attention.

What Works

Phone/Data/Basic Coms: Everything that concerns your day-to-day phoning habits works well. I haven't encountered any of the issues mentioned on the forum when it comes to volumes, coverage, call quality or loss of data. MIUI 10 re-introduces call recording which might be a useful feature for some but I haven't had the chance/need to test it out for myself.

Swipe Gestures: the iPhone-like navigation gestures are actually a welcome addition to the ROM - at least in my opinion. Coming from Android One it took me a bit of time to get used to the new thing and I still accidentally archive e-mails on Gmail when I'm trying to close the app every now and then but the gestures do make your life simpler once you learn how to use them and I know they're one of the few things I'll miss if I ever go back to OTA.

Battery Life: battery performances seem pretty much the same I had back on Android One and the phone withstands heavy usage quite well. I might need to plug it in at the end of a particularly busy day - especially if I've had a particularly long call or spent a lot of time managing social media/taking pictures but MIUI 10 never left me stranded during the day, which is a great improvement over older versions of this OS. I am not sure MIUI 10 features adaptive battery tbh.

Scrolling Screenshots: this is actually one of the features that encouraged me to try MIUI 10 and I must say I'm satisfied with the results. For those of you who haven't tried them yet, scrolling screenshots essentially let you keep capturing portions of the screen that are not visible the moment you hit the screenshot button. They're great if you're trying to save an entire email convo or a Twitter/Forum thread.

Memory Management: Memory and performances are pretty much the same I've had on Android One. On a good day, the phone (6GB version) would have about 3.2/3.3 GB free ram with the OS + Twitter, Discord, Instagram, Mi Fit, Messenger, and Telegram locked into memory. I do miss not having to manually open the recents drawer and close whatever I'm not using to free up space but the phone still performed quite well. What I will mention is that quick apps (or whatever the MIUI "no more waiting to open apps" system is called) would crash on me every once in a while but, hey, I can live with that.

What Needs Improvements

Camera: the camera on MIUI 10 is abysmal; there is no other way to describe it. Especially when it comes to video, the overall quality of what the stock camera app can produce is miles below what the hardware is actually capable of. Video turns out to be noisy even in decent lighting conditions and look as if they were taken with a cheap phone rather than the dual camera that this device comes with. 4k recording is useless if the resulting file is peppered with artefacts and remains unusable. The situation is slightly better with photos. The AI does help with taking HD pictures outdoor but the whole thing still left me wanting for more. Of course one could try unlocking camera2api and installing a gcamera mod but that could be done on just about any ROM and wouldn't be a reason I'd go with MIUI over stock. Plus, camera2api would randomly deactivate itself every once in a while, even when activated following the so-called permanent method that's available here on xda.

Wi-Fi: I've noticed consistent drops in wifi since I switched to MIUI. The ROM would show full WIFI bars only to decide the connection wasn't strong enough and switch over to data in the middle of whatever you were doing; an approach that might end up costing you a lot if you're roaming or streaming HQ video when MIUI decides your data radio is being underutilized and deserves some love STAT! This has happened on multiple routers, in different conditions and at different distances from the router/wifi antenna, making me think that the issue might lie with the ROM rather than the WIFI I was connected to.

Bluetooth: Similarly to WIFI, bluetooth also seems to have a few problems on MIUI 10. I never experienced a full disconnection but using bluetooth headphones to listen to music as I was walking/working out often resulted in the music stuttering. There are a few settings you can toy around with in the dev settings section of the ROM and I've done that but the issue was never really solved in its entirety.

What Doesn't Work At All

Screen Recording: If you're thinking of switching to MIUI to escape Google's idiotic idea that system sound shouldn't be included with the recordings of what's going on on your screen anymore, just don't bother. While the MIUI screen recorder app does allow for system audio to be captured, the audio quality is just too low to make the actual recording useful for anything more than amateur hour. Sound stutters and is often out of sync, resulting in files that you simply can't use for professional purposes. If you really need system audio for a presentation, a gameplay video or an app review, you're better off investing 20 bucks in a decent USB to jack dongle and using an AUX cable to connect your phone to a PC with audacity. Which, by the way, is also how you would do that on any android phones nowadays.

MIUI Bloatware: I've had it with these motherf***ing apps asking me for a MIUI account, even on the de-bloated EU version of MIUI. I'm not interested in a China-based cloud service that I know nothing of and I don't want to log into MIUI just to report a bug. You've asked me already, stop doing that now!

A few things I'd like to add: The support from MIUI when it comes to MIUI 10 is meh. They do have their own dedicated forum and are pretty active here on XDA but the threads are usually flooded by sub-humans spamming requests for a port to their devices and most of the people that lurk the Xiaomi site have a pretty low command of the English language. I'm not saying I was expecting top-notch support for a free piece of software but that might piss some of the less patient among us off. Most of the bugs I've discussed in this thread were already reported months ago and were either ignored or acknowledged but never fixed.

That said, I'm now looking for a new ROM to avoid going back to OTA Android One. I would need something that's at least as performant as stock Android One and whose camera can take decent pictures/photos. I've heard that camera2api is active by default on roms like LineageOS but it seems the only LOS version I could find is an unofficial port that I'm afraid will never get constant updates. Any kind of pointer or suggestion is more than welcome here!