I upgraded to an Awesome account on 500px after I had enjoyed browsing photography on the site. It took me a while to get round to attempting to upload any images of my own.
When I did attempt to upload images I found that the upload functionality is so unreliable that attempting to upload more than 3 images at once almost always results in some images failing to upload - they get stuck at "100%" and uploading is blocked. In one instance attempting to upload 20 images in one go resulted in 17 failures. It took me around 1 hour to upload 70 images. Uploading images should be straight forward and easy - it's a breeze with Flickr.
After uploading my images I realised that reordering he images in a gallery does not work. Some images simply refuse to be reordered by dragging and dropping - the only available mechanism - no matter how many times this is attempted.
I raised these issues with 500px support. They state they will respond within 2 days but after 4 days still no response. I then looked into Flickr instead and the user experience is far better - so much better that a comparison is meaningless. It would be like comparing eating excrement to a fine dining experience.
I decided to ask for my money back. At this point it had been 32 days since I upgraded my account as it had taken me a while to get round to using it. I received just a short response saying that I was over the 30 day grace period with absolutely no mentioned of the issues which I had been experiencing. Clearly they do not care about the quality of the product they are offering and the customer service. Avoid at all costs.