I've used Xmarks to organize and sync my bookmarks for years. But, I think they've stopped supporting the product and I keep getting error messages. So, I'm looking for alternatives.

I use a PC at work, but a Mac at home. I primarily use the Chrome browser (on both Windows and Mac), occasionally Firefox (on both Windows and Mac), and sometimes Safari. (I never use IE).

Naturally, I'd prefer 'free', but would consider a paid product if it worked seamlessly across platforms.

Any recommendations?