Just finished packing up my Microtek i800 to return it for a swap under warranty. It finally failed completely this week, after seven months of very light use culminating in a slow and nuisance-filled descent into flakiness. (It would be nice if scanner vendors had troubleshooting advice beyond "Uninstall all the software, reinstall all the software, unplug everything, plug everything together again, turn everything off, turn everything on, reboot three times while dancing an Irish jig. Repeat until scanner works or sanity is lost irretrievably.")
N = 1, so one can't read much into this event. But I've seen plenty of web-gossip that, on the whole, flatbeds do pretty poorly in this respect. I'd be interested in a tally of others' experiences, if folks are willing to take a moment to post. Obviously this wouldn't be a statistically representative sample, but I'm curious anyway. Which models have you owned within, say, the past three years? Which ones have failed within the first three months? First year? Ever? How many samples did you have to try of your current scanner before you got one that works?
And here's a general question: is there any hard evidence to support a presumption that spending more money buys greater reliability? Or is it an out-and-out crapshoot at any price, at least among consumer-grade scanners?