I'd go with this one,
HP Officejet 7000 Wide Format Printer | HP® Official Store over that one.
There's simply no need to buy the all in one.
As far as the ink yields, those numbers are deceptive. Black yields are based on a percentage of page coverage for 8.5 x 11 sheets of paper. The color yields are based on even less page coverage as they expect you to only use color ink occassionally for office charts and such.
You will see far less pages printed before it asks for an ink cartridge than what they are telling you, but this is because you are printing medium quality photographs at 11x17.
I've never had issues with deskjet or officejet products. This one would be worth trying out. Just don't expect it to print an 11x17 very fast.