I always go for autos as I now have a lovely collection framed on my wall, however it's always nice to have a picture too as it adds authenticity. A couple of my autos are quite rare so if anyone asks 'did you really meet them???' you can then say, yes, and here's the evidence!
Regarding autos though, for me they HAVE to be personalised. Otherwise I'd just feel like I was buying an investment or item of merchandise rather than a memory of meeting that person. Might as well just get them on ebay if that's the case, and whilst I know they're probably not worth as much I don't ever intend to sell them so it doesn't matter. If I can't get a personalisation then I'd go for a photograph instead.