Why no love for this game. I thought it was better than SMB3 & SM64. Found it more fun. So why does everyone regard it as some sort of black sheep of the Mario family?

For the HUGE gameplay change

I like it better them SM64 but not more then SMB3.

I think most people consider SMB2 the black sheep--I know I do.

People say it's because of Fludd, but I think it's because, unlike virtually every other game in the series, it didn't revolutionize or perfect anything. SMB was the first 'true' sidescrolling game, SMB3 and Mario World were 'perfections' of it. Mario 64 revolutionized 3D gaming, period. Galaxy (arguably) did it again with the gravity system, but more importantly it is perfection in the platforming genre.

Mario Sunshine... introduced Fludd?

I initially thought the game was fun. Then gradually found it dull, awkward, and clumsy. The camera was an outright nightmare that constantly fought with me and after around 80 Shines had been collected, the difficulty ramped up to such an extreme level that I felt that the game hadn't been play tested or balanced at all. The tropical theme was lame, and the NPC's were ugly.

Did I hate the FLUDD? Not really. But I found that I wanted to play the game without it and I couldn't. It was like Mario permanantly had the cape or raccoon tail. His power-ups aren't meant for permanant use.

I felt that the game was wildly inferior to the Super Mario 64, and the sense of wonder and exploration was essentially muted. The boss battle with Bowser was also the lamest ever.  Oftentimes, running around trying to clean up every spot of gunk was like a sloppy, uninspired fetch-quest.

I loved the game, thought it was a lot of fun and that the graphics and theme were great.

It is difficult but anyone that found it too difficult is maybe too used to the almost always too easy games that are are around today and have been for some time.

When I started playing games there were literally only a handful of people that could complete certain games because of thier difficulty and the dedication, patience and skill needed.
These days most games seem to be created that require a low or moderate level of skill so almost anyone can complete them (which of course makes for a more enjoyble experience for the 99.9% of people that are not skilled hardcore gamers, even though a lot of people seem to think they are) but out of this comes players that think they have some kind of skill for playing video games when really they are probably just average.

I hated collecting all of those stupid blue coins. It tarnished the game for me when I got near the end and had to go on a scavenger hunt to beat the game. There were far too many (30 on each level) and they were scattered all over the levels on each and every episode, sometimes in obscure places (especially Noki Bay). I feel like the game would have better if they had added more levels and/or episodes to extend the game length rather than an annoying task.

I loved the game too, it has more of a mario atmosphere than galaxy in my opinion... Gameplay was broken though but still a fun game.. Least favourite of the 3D marios but a solid effort

The beginning of the game was good, after that it got too much vague because of the lack of new levels / events.

To me the best level are those without the FLUDD ( not that I dislike the device ) that should tell you all.
SMS is a really good game but the Super Mario serie is filled with near perfection games ( in their genre ).