Unless I can make my money back or only be out $50-$100 at most I don't consider selling my phones. Right now I couldn't sell my Lumia 900 for more than $150 locally and even then once they see it they will want to offer $100 or less. Unless you have the most marketed phone out there and it is only three weeks old you likely won't get top dollar.
I debated keeping my HTC One X and waiting for a software upgrade to fix the issues I was having with the phone or root being enabled but a working phone was more important to me so I rolled back to a Lumia. I might not have Clearview or a larger screen but the Lumia with its single-core processor still does laps around other phones with its smoothness and battery life. I had my first 24-hour jaunt on the Lumia over the weekend which was impossible with the One X. I swear, I used the Lumia a ton. People have a tendency to use their phones when they work.
I got my Lumia 900 at BestBuy just after launch and purchased the Buy Back program for $30. They are telling me if I traded it in today they would give me $275. Too bad I need to wait until Early November and it will probably be less.