Actually the International Harvesters guns are more desirable then the other 3 manufacturers. The Winny comes next. The HRA were made fewer than the SAs, so I would guess that they are more desirable vs. the S.A.
HOWEVER, if you were looking for a Garand that saw some action in WWII, some people will take a low serial number S.A. over a HRA. I believe the majority of the HRAs were made after the war. Also, the S.A. near the 5.9 Million serial number are also one of the least problematic and higly desirable as well.
It really boils down to what interests you and what features are most important to you.