Yeah I love 500px
http://500px.com/CapturingTheNight
Go for it
One tip though if you do create a profile- They have a daily refresh at about 4:30pm AEST and this automatically drops down all the popularity scores. For example you could have something humming along at 98% and the next minute it is down to 87%. The next day after that it will be down in the 70's. So, the best time to upload something is about 5pm so that it can have the most time possible to build up popularity before it is killed by the daily refresh. If you uploaded something at say 4pm it will struggle to get much off the "ground"
All learnt through bitter experience......