[Sony Xperia S, Acro S, Ion] jonmorris:
I've got 2 Xperia S's and one has had a wipe, install and then a full reset.

The second had the wipe device unchecked and upgraded when it was started up, as most people who get ICS officially via SEUS will do. Sony always intended for this upgrade to be done without losing data after all.

I can say that there has been no obvious difference, so suggesting to everyone to wipe their device and then manually set up everything again and reinstall apps, data etc is not necessarily going to make any difference. Well, other than the massive hassle of restoring data.

I can confirm, for example, that the lagging on the home screen exists on both phones. When you go to add widgets, the delay before showing the widgets (excluding shortcuts) is the same on the freshly reset device. It's obviously an issue with the launcher.

I'm also finding that after running a couple of apps, the launcher can reset itself and reload. That was the most annoying 'feature' of my Xperia arc and I was so glad that the Xperia S with more RAM never did that. Now it is doing it at times, when the ICS updated arc is no longer doing it. What the hell?!!! Why isn't the launcher set as the highest priority there is?

I use Skype quite a lot and that's been rock solid on the Xperia S under Gingerbread, but now it can also be shut down to free RAM. Again, that's going to be a major problem for me if it isn't fixed soon.

All I can say is that anyone experiencing problems with certain apps or depending on what they've got installed on their phone should probably accept that Sony is going to need to roll out another update in the coming weeks to fix issues that are in the ROM. It isn't necessarily going to get better by doing a full reset, and you're just making yourself a load of work to try and fix some problems that have appeared post-update that will exist anyway.

Silly things like Wi-Fi not working as well must be down to software bugs. The hardware hasn't changed, yet I can see the phone drop its connection quite a bit now - and even lose sight of the SSID until I reboot, when it reappears and connects instantly. Then there was the other problem where my wiped device has now been set up with access only to Wi-Fi channels 1-11 and I can't change it via any menu (I need to root for that). The upgraded device still works. Maybe a real issue for users in countries that have those extra channels, often not used by neighbours and giving a far more reliable connection.

Still - let me add some balance here. Despite these annoyances, for the most part, ICS is awesome. The improvements to the core apps, the general look and feel of the UI and being able to adjust the font size, along with the face unlock that I can now make work almost every time by adding lots of additional face captures from different angles and in different lighting conditions (so much that I'll probably find that it unlocks with any face now!) makes it worth the update for me. Yes, even with these issues that I am confident will be fixed.

Who thinks Sony had to roll out an update to meet the Q2 deadline and already knew there were some of these issues?!!

Anyway - to summarise for those too lazy to read my rant...

you do not have to wipe your device

and doing so doesn't seem to make any difference. There are some bugs, but they're manageable and no reason to hold off!