Mycroft is less intelligent than Sherlock
Where's your argument?
Sherlock has many more "feats" as in examples of his ability, this is largely because he's the main character but still it is clear who has done more to prove their intellect.
Sherlock works alone and is capable of solving crimes Mycroft cannot even though Mycroft has the system on his side and far more resources.
Mycroft is more normal in his behavioural patterns and outlook on life whereas Sherlock displays the eccentricity present in all geniuses.
Sherlock has many talents, skills and areas of expertise whereas Mycroft only displays a few. Sherlock can do everything from telling you where you work based on the state of your fingernails to playing the violin.
No way. Even Sherlock "praises" Mycroft and admits his intellect is superior. In many instances Mycroft comes to the correct conclusion and waits for Sherlock to catch up. This is of course dependent on which source you are using though. In the Moffat series it is certainly Mycroft, in Elementary....ehhh I couldn't really tell you, in the books it's still Mycroft. The main difference between the siblings is that Mycroft focused more on analyzing and less on the work portion.