Try borrowing and shooting both before deciding. For myself, I find the recoil impulse of the SKS a bit more abrupt and jarring to my aim, despite the much lighter recoiling cartridge. The heavy M1 has the most comfortable recoil impulse of any full-powered battle rifle I've shot to date.
You can fit aftermarket forward picrails on either platform, but since both rifles eject upwards you can't conventionally center-mount a scope over the action. That leaves you with either an inauthentic-looking bubbagun, or issue sights -- and the Garand's sights kick just about every other rifle's butt.
Once I stuck a short picrail on my M1 in place of the rear sight and mounted a red dot, but the whole look offended me and I took it right back off. I prefer my milsurps to look plausibly military.
I've owned 3 Chicom SKS carbines at one time or another and sold them all, while my Garand is a lifetime keeper. Even with more expensive 7.62x39 ammo from S&B and others, I could not get any of my SKS rifles to group well on target.
Your mileage may vary, so try both and see. Actually, buy one of each if you can afford both -- the values will appreciate enough in a couple years to more than recoup your costs, if you decide to keep just one.
And if you shoot a Garand, use M2 spec ball ammo. Some fellows here may have bought their M1's when they were still relatively cheap, but they cost north of a grand today -- replacement op rods are $200+, so I treat mine gently. Check out this video:
https://www.full30.com/watch/MDA0OTYz/the-m1-garand---is-commercial-ammo-safe