I was expecting her to lipsync the whole thing, but coming out and singing live (or attempting to) was quite brave. Of course, it didn't come out right, but I give her credit for trying.
My only problem with Madonna is that she takes herself way too seriously nowadays and this brings down the fun factor in her songs/performances. You're always left wondering about the underlying agenda or philosophical/political/spiritual message (or at least I am) when in the past you would just lose yourself in her music not caring about what political agenda she was going for in her head.
Overall, I believe it was good for Eurovision, as it will make it more visible in countries that never heard of the contest, because of the fact that the actual Madonna graced it with her presence. I like the fact that maybe other people will get interested in it the way I have been for the past 26 years.