Once again in the spirit of the above posts...
I'm fine with Islamey. I'd even say that it was (and still is) one of my favorite works.
I suppose I am primed to like it, since I've listened to many of Liszt's and Alkan's bravura pieces. Many of those pieces have been some of my favorites (e.g Grand Galop Chromatique, Op. 39 no. 10, etc.).
In fact, of the triplet of pieces I see touted as "most difficult" most often (Islamey, Gaspard, Feux Follets), Gaspard is my least favorite. I find it that Gaspard (particularly Scarbo), and not Islamey, is simply empty virtuosity. Though I'm normally fine with Ondine and Le Gibet, Scarbo kind of ruins the whole set.
Oh yeah, and Petrushka is better and harder than all three of the above.
How's that for an "unpopular opinion"?