Recs.
Updated
Specs
Pros
Pro One of cheapest unlimited storage options if you are grandfathered in on a "Pro" $25/year account
For those of us who bought on to the "Pro" account when it was first offered at $25/year, Flickr remains one of the cheapest portfolio options which do not arbitrarily resize and recompress original images (Google). It is price competitive with 500px, and significantly cheaper than SmugMug or Zenfolio. Of course, if you did not get in "early", this is a con: you need to fork over $50/year to have the same unlimited storage, putting it in line with the more full-featured options.
Pro Can be set to auto-upload images
Flickr has an app on Windows, OSX, iOS and Android, called Flickr Uploadr (available for download in the tools section) that can automatically upload images to Flickr. It can even pull images from external drives and other cloud storage services such as iCloud.
Cons
Con No support for lossless file formats
Photos can only be saved as .jpg, .gif (non-animated) and .png files.
Recommendations
Comments
Out of Date Pros + Cons
Pro 1TB of free storage
Flickr offers 1TB of free storage with no limits on image resolution. This makes for a great place to store ones photos due to the high amount of storage available for free.
Con Uncertain future
With Yahoo's sale to Verizon and the apparent focus of Verizon on Yahoo's advertising unit only, Flickr's future is deeply in question. Many would say that the minimal investment Yahoo put into Flickr since it was bought in 2005 left Flickr struggling competitively and ultimately caused it to be a second-tier service, but those effects have already been taken into account in the other pros/cons.