Just signed to 500px. So far really like it. It won't compete with Flickr for a number of reasons (groups is one of them), but it actually competes with my own homepage and possibly with my blog.
I currently have my webpage hosted by the soon-to-be-dead .Mac (.Me) service. Although the site is made with iweb, the nice thing is that all my galleries are uploaded straight from Aperture, which makes my site update process very easy.
I am considering closing my website and moving to 500px (upgraded version). Downside is that there is no Aperture Plug-in to export/upload directly into 500px.
I wonder what have been your experience with 500px and if you use it just as an adjunct to your regular website. Can you see it as a replacement?
Any thoughts appreciated!