I was reading through this thread to decide whether I would upgrade from ICS to JB: Some time ago I decided against it, mostly because I love the dark look of the the dialer and contact apps in ICS (in contrast with JB's white apps for these). But I have to say: this thread has once again convinced me not to do the upgradet. I am very happy with my Xperia T running ICS. Very stable, had 2 crashes in 4 month time which is acceptable, battery life is ok too.
My only real negative comment would be that I get more complaints from people not hearing me clearly than with my previous phone (HTC). But overall I'm very pleased, would buy it again without thinking.
In other words: if you have problems, just flash it with 4.04. Maybe ICS lacks the smoothness of JB, but it's fast and I doubt if most people would noitce. On the camera side: Pictures are ok: I use Camera MX (you can change the quality/compression settings) and the default cam, but compared to a lot of phones they are pretty good in my mind. I agree that the detault compression, but pictures will always have less details than a true 13Mp camera with larger optics and sensor.
