Personally, I'd go with the SG. But it's really all feel. I wouldnt put more money into it just yet, in case you don't like playing. I'd get whichever one feels best for you, then upgrade when you feel like you're ready for a better guitar. You can always sell that one and get a majority of the money back and put it towards the upgrade.
I personally wouldn't listen to the worker. That one might totally feel better for him, but not necessarily for you. Guitar is ALL about feel. So play whatever ones you're eyeing and go with whatever one just feels best for you.