Upload & Sell: Off
I'll give you another thought. 7 years ago the predominant cameras in this forum were what? The 5D (12MP), 20D (8MP), 1D mark IIn (8MP) and their Nikon counterparts (no disrespect intended... I don't know their product line well). None of these were shooting video. Now you've got many cameras shooting 15-36MP. Let's not forget about video. Smugmug is letting members store unlimited images, and unlimited 1080p HD videos, up to 20 minutes long each.
And while I agree with pepperman that you can think of Smugmug as backup, you also have to remember that this isn't a one-way trip. Once your images and video are uploaded to Smugmug, they are also served to your viewers. I'm not even trying and I have had many thousands of unique viewers per month. I can't imagine what the company as a whole has for bandwidth and redundant storage requirements.
Then figure in the cost of prints, should you want to do it yourself. The printers, the space, the time, the ink, the shipping, the liability for an unhappy customer should prints not be right...
No thank you. The more I think of it, the greater a deal Smugmug is.