Yes if you're used to reading on a backlit screen then reading from a sony reader is definitely weird at first.
I was used to reading from an eee pc screen which as you say gets hot and I don't think any computer screen is great for reading from for a long time.
When I first got the sony 600 I found the grey background a little dull at first. However I find that I can read for hours from the screen so I guess the lack of a backlight is actually better for me to read from.
In low-light conditions I need to use an overhead light - I just have a bog-standard clip-on light. It is ugly but very powerful as it runs off 4 aa batteries. So this clips onto the back of my reader cover.
I hope it works out for you
