It’s been more than a week now and I’m still loving my SBTi. I still have my gold stainless steel S4, but find myself wearing the titanium more, the weight just feels nicer on the wrist. Yes it’s not as bling and attention catching as the Gold SS, but I don’t really care whether people notice it or not. And I really like the subdued sheen it has, and looks much nicer than the space grey aluminium IMO. Yes, some people probably won’t know the difference but my experience is that most people I come across don’t really know much about these things anyways.
I say go for what makes you happy. If you’re not entirely happy with it, might as well exchange it. It’s all down to personal preference at the end of the day.