I love Dropbox! I tested Dropbox and SugarSync and Dropbox won for me, though SugarSunc has some great features. Dropbox has made my life so much easier as I no longer have to sync the files I need for work between my desktop and my laptop constantly. I am a frequent user of RapidWeaver and Pages - both use packages that could not be read correctly by SugarSync at my last test. Dropbox works really well for me.
That said, some of my really large files take a while to appear on the other computer, but they are constantly upgrading the program and it sounds like this may have been addressed in the latest beta.
I'll be happy when I can get an account for more than 50GB. According to the website, they will be implementing a new pricing plan soon, which hopefully will have something between the 2 GB free account and the 50 GB 9.99/mo - 99/yr plan and something for those of us who want even more!