What browser are you using? Maybe try another browser or try safe mode. This is what you should see for the signup page. Just select the bottom option at the left for 5GB Free I highlighted in green.
There's absolutely nothing fishy about SugarSync at all. I've used it for ages and it's a safe and reliable site that hasn't given me any issues. I'd suspect a cache issue or something similar with your browser. If you have any malware on your PC, that can cause issues with sites not displaying correctly too.
Last edited by Ripplinger; 09-13-2013 at 02:41 PM.