Surely this filler arc was one of the more interesting ones... It managed to lock my attention to the episode the whole time ( O_O Miracle! ). Menma sure was an excelent character... He got some degree of personality... He strongly reminds me of Fye from Tsubasa Chronicles... The typical "Lazy Guy" personality, which for some reason I love!
Of course there was many holes in the plot as it was stated in this topic, but the image of self-sacrifice in the end was kind of better than having the "filler-character-always-survive" cliché...
Another plot hole I noticed is when Menma saves TenTen from the flying arrows when the group enters the village... If a smart guy like Neji knew they were entering a village which was recently set on fire, he could be more careful and detected the arrows with his Byakugan... But, oh well...