I just finished watching all of them, with the Yoda arc last. I was not disappointed. The season was fantastic and I'm only sorry that there aren't anymore. I hope this is successful enough to convince Disney to do some 90-minute story arcs or something. I have a feeling they want to put the era behind them but Dave Filoni didn't seem to rule it out in a recent EW interview.
I won't get completely spoilery on the episodes, especially the Yoda one. There's a surprise or two in there including at the VERY end. I'll just post some thoughts...
-Order 66 was a fantastic arc and did some great things for the Fives character. His interaction with AZ was great and we get to learn a lot more about the Kaminoans. I'm glad this arc gave us an opportunity to travel around Coruscant. I love the clone bar and the drunk clone who tells the air taxi driver "Hey, you're paying for all this!"
A quick note...Tim Curry does a much better job here as the voice of Palpatine. But I was pleased to realize that the late Ian Abcrombie is once again heard as the voice of Palpatine in the Clovis arc. This is confirmed in the credits. It makes sense since story arc was completed and originally intended for the 5th Season.
-The Clovis arc continues the goodness and gives us a look at the Anakin/Padme relationship and we get a pretty good scene with Anakin and Obi-Wan as well. The end of the first episode has a terrific action sequence.
-The Jar Jar and Mace storyline is actually pretty good. It has an Indiana Jones/80s fantasy vibe to it. It's a good adventure for the Mace character.
-The Yoda arc is pretty epic and answers a few things. They might have waited a long time to do another Yoda story but it was well worth the effort.