I tend to feel that O. Sagat and Dhalsim are about equal after Boxer. O. Sagat is definitely the easier of the two to play (and least varied fight), but a good Dhalsim can make me feel like I simply have no correct options in the fight.
I think Dhalsim’s bad matchups are what makes him worse than O.Sagat and Boxer, not that it doesn’t make him dangerous.
Boxer really doesn’t have any bad matches except maybe Honda and O.Sagat but even against them, he controls the space in front of him and has unbelievably good block strings and combos and his super is crazy good.
i think a good chun is a damn bad matchup for boxer to beat. i have seen japanese chun player almost only lost to o.sagat and ryu…
sim is gd but u need skill…also, i have main problem against chun and claw…
as far as i like sim, i really think akuma is no.1 in st… what u think about his brainless matchups?? e.g. just air fireball zangief to hell!!!
And what bad matchups are these?
NKI’s Chun 
Actually… most Chun’s, right?
Mainly Claw, that’s a most horrible match up for Sim. But indeed, Chun and Boxer can be an uphill battle as well, it’s all good until they both get that super bar filled up, then they both have the upper hand.
That’s also one of my points when I say that boxer is the best, that is when he has that Super bar ready to go.