By little printers, I guess, your friend thought about Dye-Sublimation printers. Personally, I went with one just for small prints. Though more expensive per print than lab, I find quality of the prints way higher than ordinary lab prints, not to mention full control over the PP if you're not satisfied with outcome. I have an older version of Canon, Selphy-510, and only problem so far that I had are the dust particles that are usually found on the first paper in the cassete. This printer retracts paper 4 times (in and out of printer - doing layer by layer of the colour) therefore allowing dust to stick on the paper before adding another layer over it. But, as I've said, usually I find "dust scratches" on the first paper only, and the rest comes without any noticable problems.
I think newer versions are doing whole process inside of the printer, but I've might be wrong.
Otherwise, it's great little tool which you can take on the shoot, print some samples for clients, do TFP and so long. Actually, 4x6 I do only with this printer since I have it
For me, it's irrepleacable.
Cheers
Vlad