Senator Armstrong boss fight

Man I just beat it on Revengeance difficulty and feel so good right now. The first time I fought him I got my ass kicked, but when I went back to it I found it a really enjoyable battle with a freakin' kickass theme. Has anyone here beat the game on Revgengeance yet? How difficult did you find it? Also how enjoyable did you find the bosses of this game, in contrast with those of the main Solid series.