I'm interested in some of the same questions you are but don't have a lot of answers yet.(posted 8852 days ago)I was killing time at a tire store a couple of months ago (waiting for a new set of tires) when I noticed a couple of magazine articles about photo sharing sites. These were PC magazines, not photo mags. (Most of the names you mentioned were in the articles.)
I wrote down all the names and started to look into some of them. I took a quick look at four or five of them and just plain ran out of time and interest. They all seemed like the quality would be similar to what I would get from the drug store on the corner. The emphasis seemed to be on the techie, internet, sharing part of it, not quality photo enlargements. They seemed geared towards the consumer with a medium resolution (1 Megapixel or less) digital camera and no way to print the digital images. I don't remember any of them offering B&W printing.
I do have a freind at work who took my list and looked at a bunch and choose shutterfly.com. He said they seemed to have the easiest interface for those who wanted to look at your photos. He knew his dad and family would get lost in some of the other sites and never figure out how to see the photos he was trying to share with them. He also liked the fact that he decides who can see his photos. It's not just wide open to anyone with the computer and a modem.
What I'd really like to find is someone who will do true B&W printing on archival materials from digital files. (You may remember that I was one of the winners of George Shaub's "The Digital Darkroom: Black and White Techniques Using Photoshop" book during the chat he had a few months ago at photohighway.)
I've had some success using Adobe PhotoDeluxe to print B&W images on my HP Deskjet printer. Some were from scanned color prints, others were scanned from B&W originals. But the prints are very easily scratched (the ink just sits on top of a very non-porus inkjet paper) and I know the prints are not very permanent. I expect they will start to noticably shift in three to five years. Plus 8x10 is as large as my hardware will go. It has also taken a lot of effort to get a neutral B&W print. Even greyscale digital files tend to end up with a color shift. It's still a color process (paper and ink jets) and getting rid of any color shift has been very hard. (The professional photo service I use for traditional B&W says they have the same problem when printing greyscale digital images. Their prices are very high also. Many times more than traditional B&W. That's one reason why I haven't used them for digital printing yet.)
I would really like to find a quality photo service that will print digital images on a nice FB (or even RC) B&W paper. This would eliminate the nasty color shift problem inherent with color papers or color printers that are suppposed to "ignore" the color info but don't seem to. It would also make them more permanent and allow larger sizes. And hopefully they would only cost a couple of times as much as traditional B&W enlargements, not five or six times as much.
If you could find a service like this I would be really interested.