Well... it's been 3 months now. My grandmother has gotten accustomed to having Presto around. You know a piece of technology has been formally adopted into someone's life when they start taking it for granted.
For example, the other day she called to let me know that the ink had run out. That makes usage about 1 high capacity cartridge per month. Not bad considering she seems to be going through a whole ream of paper a month too.
I do have one complaint... The Presto Mailbox only uses a single cartridge. That means it creates black by printing CMY together. That makes for a slightly less black than actual black. It also means that color ink usage is higher than it realistically should be. In turn, the higher ink usage makes the total cost of ownership higher than it really should be.
Altogether, it's been quite a surprise as to how well the system works.