[dwig]

I don't have much personal experience with a wide range of "modern" dedicated ereaders as my previous devices have been general purpose devices (palmtops in the jargon of the day, some tablet configuration) and spans a large portion of portable computing history. My experience with those has been rather good in terms of reliability:

HP320LX: served well for several years and retired when replaced by a subnotebook (Fujitsu). It did later develop issues with the circuit flex between the display and keyboard halves.

Fujitsu sub-notebook: still works perfectly except battery life is measured in 10s of seconds and its otherwise obsolete. It worked great as a notebook but was too big for an every day ereader.

Sony Clie T415: replaced Fujitsu as a reading device. Only "failure" was the latch/ejection mech for the Memory Stick cards, a classic Sony issue. Retired in perfect working order.

Sony Clie UX50: replaced T415 because of much better screen, larger and backlit. Served well for years and years. Serviced once to repair WiFi (bad design of chip socket, cronic UX50 failure). Retired in perfect working order, other than poorly functioning MS slot latch, due to diminished battery life (~20min) and advancing display tech.

Kindle 3: current device for the last year and a half. I'm very satisfied with this one and don't expect to replace it anytime soon. I'll probably add an Android device (probably tablet rather than smartphone) in the not too distant future, but as a replacement from my 12 ton Dell notebook rather than the K3.

I'd have to say only the Clie T415 was a general disappointment, though none were mechanical or electronic failures (I forgive the UX50 its one warranty service trip). Its reflective mono LCD was dim and too shiny making it tricky to read in many lighting conditions, particularily office lunch rooms or outdoors. None of the early devices were really usable outside, even in the shade, except the LX320.

For a long time I swore that a device had to have backlight to work for me (if you dig you may find an ancient comment or two to that effect here at MR). The eInk displays have finally advanced enough that I don't find that necessary anymore. Any adequate reading light for a paper book is adequate for my K3. That was not the case with the old Clie T415.