I was never told that Japan likes roguelikes more than the west either!
Yes/no. The Mystery Dungeon lineage has great weight associated with its past successes, but it doesn't do all that great overall.
Also, it's important to remember that basically every roguelike that comes from Japan is derivative in some fashion of these games. We have a lot more variety in what sort of Roguelikes you could play than you get there. Japan doesn't like to branch out or experiment genre-wise a whole lot, unfortunately.
Admittedly, I'd love to see the PC Shiren Gaiden game become available. I would grab that in an instant if it wasn't 40k yen used. Tempted me to slap together my own Shiren-alike because they're really not that hard to make.
edit: also, as an IaMP fan, I don't see much point in voting for IaMP, personally! It would totally bomb.