Everything in one place - all the journal articles i should be reading, and the novels that i actually am reading are in one handy place.
It is very lightweight
If i fall asleep while reading it saves my page and powers itself down
If i start reading a new document when only half way through another it will remember where i am in both.
It is not backlit, so no headaches from screen glare
Its deal well with .txt and .pdf files (i have not tried any others), and has an option to change the two or three columns of text in a pdf into one single column with the end result of making it easy to navigate.
It has the option to zoom in or out changing the size of text displayed.
The 'e-ink' makes it feel much more like reading a book than i thought it would, and the display is brilliant in strong light
It has low power usage - it only uses power when you turn a page.
Many of the 'classic' books are out of print and available for free via project gutenberg
Small things like having to roll over to read the other page when reading and lying down, or having to juggle a book to turn the page when it is a particularly large book are no longer an issue (Not that they were real issues to start with, but it is the small things that make the ereader nice).
No backlight means i still need to have a light on to read in bed
It has crashed a few times, though easily fixed on most occasions this is annoying - a real book never crashes
It is a much greater risk - losing one book is not bad, losing all of them on one device would be bad
It is in greyscale, so no colour pictures, which can be annoying in graphs in academic journal articles
I can only charge it via a computer - real books do not run out of power
E-Books are not cheap. It has become a pet peeve that e-books are actually more expensive than real books. I am aware that there may never be a great difference in price as the majority of the price of a book can come from the costs of creating, and marketing a book rather than the reltively small cost of printing and distribution, but i still feel that e-books should be slightly cheaper, and definitely not more expensive.
Overall i can see a place in my life for an ereader, and it will get used regularly, but i will still keep buying second hand novels and building up my library of 'real' books.
I was tempted by the kindle with it's 3g connection, and by the ipad with its... well, everything. I decided against them because i was looking for a device to read journal articles on, having an internet connection would not help that objective, and all the other features i have on other devices. I like having separate devices for separate purposes. I find it much easier to read a journal article when i cannot have instant access to facebook.
As i mentioned earlier i have been using my ereader to read a few novels. As i have access to a large number of free e-books i have been taking advantage of this and reading a few of the classics i truly enjoy. I read little women, siddhartha, the scarlet pimpernel, the three musketeers (wonderful story), and i am now making a start on re-reading the sherlock holmes stories, starting with A Study in Scarlet. I am about a third of the way into the story, and very much enjoying it. I have always loved mysteries and enjoyed the recent tv adaptation much more than i had expected. Re-reading these books is like re-discovering old friends, remembering the (imagined) adventures of my youth.
I am hoping that more SF stories will become available via the gutenberg project - surely some of the good ones are out of copyright now?