I think overall it's been an absolute success for X Japan.
There was a relatively good turn-out, a strong supporting contingent and they also made a fairly good impression onto those who have never heard of them before. Watching those MTV interviews yesterday, both Wolfmother and Switchfoot both commented on how fantastic X Japan were sounding. I'm still waiting for more press to become available, but from what I can gather the general consensus is positive. A review which criticised a band for "sounding 1982" isn't really negative in my eyes - that's like saying that U2 are bad live because they sound like an 80's band.
From watching the videos back I think it's also pretty plain to see that they were all very nervous. Yoshiki messed up on drums more times in a show than I've ever seen, Heath was also particularly sketchy and Pata had a little scare at the start of the show when his guitar strap came loose. I suppose it's nice to see that despite their godly-rockstar status and no matter how many times they have headlined Tokyo Dome, doing something like this they're merely mortals like the rest of us.
It was also nice to see Yoshiki wearing his neckbrace for once, especially given that he was instructed 14 years ago to never play drums without them. Perhaps the myriad of operations has finally gotten through to him that he needs to start to take care of his body a little more if he wishes to have any prolonged career in music.
I also noticed that Heath has toned his visuals down dramatically, to the point of not even wearing makeup. Why?!? Since X Japan reunited he has always looked fantastic, perhaps nerves got the better of him in that he didn't know how it would be received by Americans and as such he decided to play it safe. Sugizo was looking as visual as ever, and Toshi was sporting his new cyber-suit look from the January filming events (personally I prefer his Tokyo Dome 2009 attire).