ICS has completely transformed the experience of using my device. When I replaced my G300 with the San Diego, I was initially somewhat underwhelmed; disappointed, even. The G300 had felt like a real leap from the San Francisco it replaced. Out of the box it wasn't great, but with the updated ROM it flew. It was so much faster and more responsive than the San Fran. I couldn't believe it had only cost a few pounds more. I expected a similar leap with the San Diego; a device retailing at twice the price of the G300 on release. However, I was disappointed with the smoothness of the transition between homescreens (even using Holo Launcher), I found typing far harder (I kept hitting the wrong keys), the battery life was disappointing compared to what I was used to and it just didn't feel as responsive as I had hoped it would. I admit I never tried using the Xolo version of Gingerbread though, so all this is based on stock Orange.
ICS has changed everything. The device is so much more responsive. All the transitions happen swiftly and smoothly. Chrome browser is a treat to use, with content loading and pages formatting far more swiftly than I have been accustomed to. The choice of ringtones and notifications is excellent. It is early days to judge the battery life yet, but since I updated yesterday afternoon it hasn't drained anywhere near as much as I would have expected under the stock Gingerbread despite my increased usage.
If reports of improved GPS fix time and no-clicky sounds in video recording are true then I am one happy bunny. I am also keen to try root so I can install Ad Free and perhaps change the alarm sound.
I am now back to the feeling that I can't believe this phone only cost me £140 (after £30 Quidco, which Orange actually paid through in a matter of days). A definite step up from my G300 now, even when it was running Infusion.