Okay, I myself have been getting a bit annoyed with Philips on this one and have also been getting nowhere with the email and chat facilities except for the blanket "it'll be released when it's released" mantra. So I asked how I could escalate the matter this morning and was given a phone number.
After a few minutes, I got through to a member of the technical team, who came back to me to say, although specific bugs couldn't be listed, the priority of the upgrade was to fix the picture and sound issues (i.e. the audio sync problem that I've seen a few times as well) and issues with the EPG. When I pressed further, EPG issues included the likes of timers being set for several different +1 and SD channels when something is set to record. She mentioned she'd been speaking with a few customers to get more info on all the issues that have been reported and, she effectively said that they were looking to fix "all the issues reported so far" in this update. I also asked about the corruption in the main Timers list and she confirmed this was one of the issues that had been reported and was being looked into.
She also said the upgrade was being tested and it should be released soon. When I queried the end of July release date currently being touted by email and chat support, she said it should be mid July and end of July really was a worst case scenario.
Importantly, I really got the impression this lady was on the front line of developing the patch - there was no hesitation in any of her answers to my technical queries about the bugs on the box (and she was familiar with all of them!) and she spoke specifically of "we're looking to fix this", "I've spoken to customers with the issue to get more details" etc. as though part of the team working on this.
I have to say, it's definitely put my mind at rest a little now I've finally managed to get a response and I'm more confident we will see some big improvements from the upgrade when it arrives (hopefully as she says mid July), within the next week or so. I just wish it hadn't been so difficult to get there, but then that's a big company for you - it's all about speaking to the right people.