[Sony Ericsson Xperia Mini, Mini Pro, Xperia Pro, A] PetterW:
This ROM/Kernel combo is a great one, I must say. I want to share my experiences running it, and maybe somebody has more tips on how to improve even further. Feel free to ask questions as well.

-- some basic info --

The phone is rooted, obviously.

I have a fast 32 GB card and Mounts2SD app, so storage of apps is not an issue in any way.

I use Nova Launcher, Xperia Keyboard (with gestures and two languages), MyAndroidTools for managing apps and services, and Greenify to hibernate some stuff.

I limit background processes to 4 under developer options. Sometimes I kill apps with a long-press of the back button to make room in RAM for the next activity.

-- what to disable --

I'm pretty into Gmail Inbox, but in the end it was too slow to run on the phone. And besides a stupid parking app Inbox was the only app that needed Play Services, so in the end it had to go. You see, Play Services is the main thing that will choke the phone on random occasions. It's got 325 services(!) and counting, so no wonder that it runs amok every now and then. Just cut them away by disabling them in MyAndroidTools.

Play Store is also something that is not a very nice background thing on a low-end phone, so I disable that, too. It's relatively easy to enable temporarily if/when I need to install something.

I have location services disabled. Navigation is therefore a no-go which is kind of a bummer - Google Maps is also Play Services based and won't run on 400 MB RAM anyway, so don't bother. Maybe there are other navigation alternatives around for low-end phones, IDK?

** A note: Play Services and Play Store irritate me as they turn on themselves spontaneously every now and then. Every few days the phone will turn to quicksand and when I diagnose there's always Play Services running again, even though it's disabled in MyAndroidTools. I would really like to have those two be well-behaving citizens **

-- apps --

Shuttle is a nice music player for this phone, I have about 25 GB of music on the card and it manages well.

Mailbox by Dropbox is lean and fast and a fine alternative if it wasn't for the fact that I'm not able to type in more than one word when replying to a mail - bit of limiting for a mail app wouldn't you say?

Twitter, Trello, Slack, Dropbox run fine although I won't run widgets due to RAM limitations.

Business Calendar is my longtime favorite and it works well. I tried upgrading to BC2 but that's not for this phone as far as I could judge (and with no new need-to-have features).

Opera Mini works for me, seems to be pretty conservative on RAM if a limited number of tabs are kept open. Of course, not everything renders optimally, but on the other hand the data savings are great so you can even surf decently on Edge connections, which come in handy sometimes.

The SJB camera works great, as does the FM Radio - and no problems ever with Wifi which I had with the phone on other ROMs previously!

No games. Not my thing. Not on a 3.5" display anyhow.

-- final words --

With the setup described here, this phone is still very much usable. Sure it's not the fastest but hey Zen right? And you won't be able to run any app comfortably, but the abovementioned make my workday more than manageable. Kudos to the ROM and Kernel developers, and to SonyEricsson for a still-great phone in a really pocketable package!