Think the first time I went was in 2010, then I was there again in 2012 and this year. One thing that I have started to realize is that the festival seems to become more & more of a fancy parade with Brazil + etc. related theme on top of a carnival touch. I mean in a positive way, this is what I like about Japanized events, anything goes. Rather than focusing only on hot dancers like the original carnival, they make it more elaborated with wider and creative ideas integrated into each team's parade & costume. Interesting themes/ concepts include Hawaiian, Alien (see below), some kind of Gladiator (see below), bugs/ insects, etc. I mean I really admire their creativity, although not very sure about the relation to the samba carnival :D I believe it makes the event more interesting and dynamic, you dun really know what to expect and you can be sure that the scene will always be fresh every year. Another point to add is their costumes/ props' seriousness, every piece looks really fantastic. It gives an idea that they carefully decorate and didn't pick it randomly from a 100-yen store.
(M-E + Canon 85/1.8 LTM)
-The Bug Theme-
I really like this one, they made it like the airport.