I used to have a Kindle and had free copy of BOM. You can get any .pdf file converted and transferred to Kindle. The device is lightweight. It's processing and search features exist but are so slow they are almost useless. I used the Whispernet to subscribe to the Wall Street Journal which I found convenient. But after I moved to Canada, there was no more Whispernet (It is now available, but my device would not be compatible). After several months, I thought I would try to download some files from my computer via the USB interface, but the device was "dead", perhaps from the battery. I didn't want to pay to get it diagnosed or buy another battery, so I scrapped it.
The books I "bought" are still on my Amazon account, but I would need another Kindle to access them. I would like to get an iPad for book reading, but the first version is pretty heavy. It also has a battery which would be expensive to replace.
I would suggest you buy such a device with the idea it would need to be replaced every 2 or 3 years. I would also look for media that is device-independent, but good luck with that.
So a netbook or iPad might be more flexible than the Kindle.