I'm not a pro, but I love Smugmug and their commerce offerings looked extremely promising and they tout the SEO quite a lot. I went with Smugmug mostly because their Lightroom plugin is absolutely incredible. Not only does it have a great number of options, it is capable of syncing metadata without re-uploading the entire image. You can easily publish a collection with all necessary settings: password, cart options, gallery style, etc...
I tend to upload all photos to password protected albums that are really just for me. Much of that serves as an offline backup. From there, I use Smart Galleries to pull images from other galleries using keywords. On my front page, I have some favorites shown publicly (need to work on that.) Elsewhere, I use password protected or unlisted galleries that might show one event, such as "Cub Scouts", "2014", "Pinewood Derby" and I can share that with other parents. If I were a pro, I'd probably still tend to upload all, then create Smart Galleries for the customer using a keyword like "include" and you could change what images the client could see simply by adding or removing that "include" keyword in the metadata.
The only complaint I've really seen about Smugmug is how their branding shows up in various places and that it can be a chore (maybe impossible in some places) to suppress it.