Tough to say, IMO one is not really better than the other but boy are they different. I did LG this morning and got a great workout and I've got a nice dose of DOMS, GS is awesome but for me has dread factor as my neck doesn't much like barbell squats, but GS hits the hamstrings (especially biceps femoris) like no other. For me it's an apples and oranges thing, ankle weights and bands make the same exercises feel very different. Either way you will definitely tone your legs.
Both are great to have. You can minimize the dread factor in GS Legs by doing the standing work one day, then doing the floor work a few days later. That stability ball work is KILLER!