The extendeds really help make a lot more sense of scenes if you haven't read the books. This is basically the same. Poor Faramir in the 2nd 2 movies got hardly any screen time and came off kind of whiny in the big screen versions but in the EE they made him actually interesting and a character to care about.
I wasn't overly big on how they redid the Saruman scenes but I'm not screaming in agony either. You couldn't have expected everything from the books to make it to the screen, it'd probably have taken 5 movies to cover it all. I missed some parts, but I'm certainly glad there wasn't as much singing as in the books.
The Scouring would have been plausible if there was 4 or 5 movies but being as there was only 3, and RotK without EE was clocked in at almost 3 and a half hours and EE at 4 hours 10 minutes, they'd of probably pushed the movie a bit too long adding that in properly, so I can concede that point, but if that's the biggest thing your looking for with the Extended, you may be disappointed. But a lot of the added footage was quite interesting and The Mouth of Sauron was great, though anti-climatic.