Half speed records, are they any better ?

I have a couple half speed masters that don't sound anywhere near as good as the original first pressing.  George Benson's "Breezin' comes to mind as does Steely Dan's 'Aja'.  I am probably not the best to offer advice as I only have maybe 25 titles, and none of them have 'blown me away'.  I seem to much prefer a good 1st pressing, but that's me.  

N 

atmasphere,

Thank you for the education.  Makes total sense and explains why the old Londons and Deccas sound so good.  I am wondering though,
why is it that some half speed masters don't sound as good as their normal speed 1st pressing counter parts?  I appreciate someone explaining this. 

Norman