Several months ago I wrote a brief review of the Sony Reader (PRS-500). The upshot was that I was extremely happy with mine, with just a couple of small caveats. Fast forward to today and I now have something else to compare it with, the Amazon Kindle.

There are plenty of comprehensive reviews of the Kindle floating around so I don’t think we need another one. Instead, I’ll focus on comparing it with the Sony Reader.

The Kindle seems to share the same screen as the Sony Reader. Holding the two side by side, I can’t find any difference in the quality of the output. The screen requires slightly more light to comfortably read than a paper book would since it isn’t quite as high-contrast as ink and paper. But that’s really a minor gripe.

As far as battery life is concerned, the Kindle can easily go for multiple books without recharging the battery, particularly if you turn off the wireless functionality. With wireless enabled, it seems to drop to around half power in a couple of days—I typically recharge at that point so that I never have to fear running out of juice in the middle of reading.

Wireless access
The wireless access to the Kindle store is fantastic. I like to take my Kindle with me anytime I’m going to be sitting and waiting for something for more than a few minutes. With my Sony Reader I had to be proactive about making sure I had additional books loaded and ready for after I finished what I was currently reading. I find that I have pretty distinct reading moods, so having the flexibility to add content on demand is a really big plus for me.

There were a lot of complaints flying around the internet after the Kindle was announced relating to its format support and DRM. All of the purchased content from Amazon is “protected” by DRM. This is really no different from any of the other major readers. I’m not bothered by it.

PDF support
The other main complaint was lack of PDF support, and I read a number of blogs that cited that as a reason why the Sony Reader was superior. The Kindle supports Mobipocket formatted content, and there are converters from PDF to Mobipocket available. The output looks pretty rough, but no worse than the built-in PDF support on the Reader. Overall, I think it’s a wash.

The last area I wanted to touch on is the interface. The most obvious difference is that the Kindle has a full keyboard, needed for its online functions, search, and the included mini-applications, like the dictionary and thesaurus.

The Kindle has very large next and previous page buttons that are really accessible—too much so sometimes. I often accidentally press next or previous page when I change my grip on the device. It’s not a big deal, but it’s definitely annoying when it happens.

On the other hand, the Kindle has a really ingenious scroll wheel and select cursor that is beside the screen. Since it’s not part of the eInk display itself, it doesn’t suffer from the slow refresh rate of the main screen. Oh, and it’s shiny.

Overall I’m very happy with my Kindle. It’s still not perfect, but it’s better than the Sony Reader in every category that matters to me. It’s a major evolutionary step, and the addition of painless wireless access definitely raises the bar for ebook readers.

Disclosure: Amazon’s Jeff Bezos is an investor in 37signals.