I don't really want to turn this into a vs. thread (already had that fun last week in Marvel Films forum,

)
So, I'll just say critics did acknowledge for the most part that SM3 was vastly inferior to the second movie in that franchise and not up to snuff with the first for that matter. But Raimi still has a love for these characters and does try to explore their world, their psychologies (though some are simpler than others in his movie coughVenomcough) and gets into some weighty themes.
He also has a very quirky visual presence that jumps from all sorts of genres and while some may hate the dance scene that is classic Raimi and film critics tend to be film nerds so a reference to the AOD-Raimi we haven't seen in over a decade made some very happy (check Evil Dead boards at IMDB).
FF:ROTSS is classic Hollywood sutdio committee filmmaking. Safe, not very deep and boring. But it was remarkably faithful to the spirit of the '60s comics in some aspects (I would argue the sitcom angle overshadows that though) so fans will love it. But you do have to wonder where is the Silver Surfer who spoke siloliquies as if he was performing Shakespeare has gone in this movie and why Doom is still a a punk. I won't mention Galactus.
But FF satified what fans wanted to see (cool Silver Surfer and fun tone) SM3 did not, with odball sense of humor artistic flourishes and Raimi spending more time on his interests (Harry/Peter and Peter/MJ) t han fan favorite Venom. But to make it short I think why it got better reviews is because of what Peter Travers said (at Rollingstone Magazine):
" The third chapter in the Spidey saga (a fourth is in the planning stages) is uneven, ungainly and frayed at the edges but there's lively mischief in it still. My guess is that when the summer blockbuster season finishes pummeling us with formula, Spider-Man 3 is going to look like one of the few that was touched by human hands."
FF is the formula he speaks of. That is why critics hated it. Personally I enjoyed FF2 inspite of this.
Don't hurt me now.