Well I don´t have a SR yet but I did a little research since I am on lookout for one to.
But here is waht I got:
The HSGI stuff seams to be nice...but just if you wear it with the plates. The little Weesatch could be ok without the plates. But you would need shoulderpads anyway.
The HSGI rigs come with a backplate/molle carryier. Also soem say that the HSGI rigs are not so front-heavy.
The STRIKE comes with shoulderpads but no back. For $60 extra you can get a back (platecarrier/moley) to. This one is rated to be ok without plates. If you carry 6 or more mags it will get fron-heavy...but with a plate it will get heavy anyway. Militarymorons.com is a place to take a look on the strike. He put a bladder on his backside of the STRIKE.
Right now I am looking toward the STRIKE. I can carry it as a ChestRig only, I can add a Backplate-kit if I want to, I can just put a cammelbag on it without plates, I can carry a ruck with the SR strapped on...
But he HSGI comes with back-side and inside-mag.pouches allready and it is called to be not so front heavy like others...when wearling no plate....
I don´t know....yet
heHope you guy´s who own all this gear can tell me if I am right or wrong....still looking for the right gear.
Take care.