most of my projects are updated and as expected the update to TYPO3 4.3 hadn’t been a problem. everything went well and the new backend look is charming.
all went well
the sites get even faster,i did not instatiate the new caching factory, though. the new recycler is great and a must for every mid sizes website. the new recycler works way better when deleting tons of entries from a table.
the update of the extension templavoila to version 1.4.1 was also no problem, though on the biggest site i administrate (with more than 60 backend editors) i’m preparing for some bug reports. newest tv style finishes the new interface design at all – a feature that impresses them all is the drag and drop feeling.
tt_news 3.0.0 – don’t update live
but beware of upgrading tt_news too fast from version 2.5.2 (which is the highest in the 2.x branch) to 3.0.0 if you not have checked how the templates change! the whole morning was consumed by the fixing of tt_news styling. tt_news come with new caching mechanism that promises to speed up some data work that needs to be done every time news are rendered. tt_news 3.0.0 comes with that cool new update script that checks for possible problems – where it removes relations to templates as far as i remember.
falling back to the standard template coming with v3 the title wrapping changed from h3 to h2 and stuff like this – thus breaking the layout of the website on every page. if you’re using tt_news as main function for a big web site that should not be done “live”. 
also there had been problems in the realurl configuration after the update. solution was to grab a selection of the content of res/realUrl_example_setup.txt in the tt_news ext folder and drop it in typo3conf/realurl.php and so the errors were gone.
i don’t know why this was necessary, but tt_news showed a nasty red bordered error if now singlePid was set (which can be done in the constant editor) even if the site worked before with tt_news 2.5.2 due to single-page target was set per plugin settings.
another thing you might want to avoid is the output of some php stuff before the website’s head section.
all in all i’m happy away how simple it’s getting to create web content management. many of the tricks you need to learn are now turned into guides (i.e. compare database is the final step of the update in form of a button in the update wizard process – before that you just “needed to know” that).
great job TYPO3 core team!
/dev/sr0: failed to grab associated sg device