I have been doing these comparisons between other Kindles in this thread...
$69 Kindle 5 vs. Kindle Paperwhite vs. $79 Kindle 4 here:
http://www.kboards.com/index.php/topic,129956.msg1921055.html#msg1921055
And Kindle 3 Keyboard vs. $69 Kindle 5 vs. Kindle Paperwhite here:
http://www.kboards.com/index.php/topic,129956.msg1921549.html#msg1921549
And my Kindle PW review is here:
http://www.kboards.com/index.php/topic,129852.0.html
Now it is time to put the venerable Kindle 2 against both the Kindle PW and the $69 Kindle 5. Is either a good upgrade from Kindle 2?
The looks:
The white Kindle 2 has held up remarkably well. While I think Kindle 1 was a bit weird looking, Kindle 2 already has that timeless design most Kindles have. Kindle 2 is, however, next the Kindle PW and Kindle 5, absolutely huge which makes its 6" screen seem smaller than the rest although it is the same size.
Out of the three, I think Kindle PW looks, with its very simple lines and rubbery sides, the best and Kindle 5 and Kindle 2 are tied for second position. All look good, Kindle 2 is just a lot bigger and heavier than the rest.
$69 Kindle 5 is the smallest and lightest, if that is a consideration. It is a LOT lighter than Kindle 2 and even Kindle PW.
Amazon lighted leather cover:
Kindle 2 didn't have a lighted Amazon leather cover, but it did have a very good regular leather cover from Amazon, much like the Kindle 3 non-lighted cover. Kindle PW also has a very nice non-lighted leather cover from Amazon, which closed up actually looks a bit like the Amazon 2 cover because they both have a metallic Kindle logo on them - something Kindle 3 or Kindle 4/5 lighted cases didn't have.
Only lighted case is for the Kindle 4/5, but as far as non-lighted cases go, Kindle 2 and Kindle PW have the better ones. Kindle 4/5 also have an official non-lighted case, but it lesser quality of all these. Kindle PW case is the best with the magnetic closing mechanism and the device sitting tightly inside it. Kindle 2 case lets the device wobble a bit in its metallic clips, but is otherwise a very solid, high-quality cover.
So, if you are used to and like the Kindle 2 cover from Amazon, upgrading to Kindle PW with Amazon cover is a safe bet. The Kindle 4/5 official case is a bit more of a mixed bag. Perhaps consider an alternative there, for example:
http://www.amazon.co.uk/gp/product/B008635H4M/ref=noref?ie=UTF8&psc=1&s=electronics
The software:
Unlike Kindle 3 Keyboard, which still runs pretty much the latest Amazon features (not quite all, but most), Kindle 2 software is starting to show its age. It too did get a 2.5 software update, which brings crisper fonts, collections and social media support, but there is a lot more missing than on the Kindle 3 Keyboard which is fairly equal to Kindle 5 in software-terms.
Some new things Kindle PW and Kindle 5 would bring to a Kindle 2 owner are the option for partial page refershes (instead of blink after each, this is not available on Kindle 3 either), support for panel view comic books and children's books, parental controls and some other smaller features. Kindle PW would also include X-Ray, translator, cover view for books etc. that Kindle 2 or Kindle 5 don't have.
Not to mention that the new devices are inherely a lot faster and run their software better. So, in terms of new software features, the upgrade certainly carries weight. However, again as a reminder, Kindle PW or Kindle 5 do not support audio of any kind! So if you need audiobooks or text-to-speech, consider upgrading your Kindle 2 to Kindle 3 aka Kindle Keyboard (still sold by Amazon).
The function:
There are a couple of things I must mention about the Kindle 2, when compared to Kindle PW and Kindle 5. First is, since it is bigger, the second generation Kindle does probably have the best hardware keys and page change keys of all Kindles. PW obviously is touch only (but works well both in page changing and virtual keyboard), Kindle 5 has smaller page change keys that are harder to hit (not hard, but harder than Kindle 2) and no hardware keyboard, so if you must have a keyboard, Kindle PW's virtual one is better than the scroll-character-by-character Kindle 5 keyboard which is fine for short search words, but not much else. Kindle PW's virtual keyboard may be the best keyboard in any Kindle. The Kindle 5's 5-way controller is a bit better than the control knob on Kindle 2, in my opinion, though.
The second thing is the overall speed at which the devices operate. Kindle PW is fastest, Kindle 5 is fast enough and Kindle 2 slow as molasses. So, the newer Kindles change pages faster, operate menus faster, do everything faster. It is a quite distinct difference between Kindle 2 and later Kindles. Even Kindle 3 Keyboard is a lot faster than Kindle 2, which is in a slow-league of its own.
If you need hardware keyboard, an upgrade to Kindle 3 aka Kindle Keyboard might be useful. It is a lot faster than Kindle 2 and has a better screen.
The screen:
Kindle 2 screen was a controversial star of its time, not unlike Kindle PW now. It had less contrast than the first Kindle and the infamous sun fade problem plagued some units.
Looking side by side at Kindle 2, Kindle PW and Kindle 5... I can safely say that the controversial-in-itself Kindle PW has finally found an earlier Kindle which is beats in text blackness. So if you are upgrading from Kindle 2 to Kindle PW, you should see an increase in text blackness on the new device (the PW frontlight is a different consideration though, you might or might not like it, remember it can't be fully turned off). The Kindle 2 is clearly the most light-texted one of these all and it also has a darker background than the others. The Kindle 2 software update up to 2.5.8 does make the fonts a little crisper compared to 2.3 though, but still not enough to touch the Kindle PW.
However, again, the undisputed king of black text is the $69 Kindle 5. It is so much blacker than either of the two competitors, new or old, that it isn't really funny anymore. For me, best of bunch is again the $69 Kindle 5. Kindle 5 has by far the best pure e-ink experience and for plain old reading its size and feature-set are pretty much perfect, if that is sufficient for your needs. If you need audio features or hardware keyboard and are coming from Kindle 2, consider the Kindle 3 aka Kindle Keyboard instead - it is still sold by Amazon. If you want all the latest software tricks, Kindle PW is the way to go, but beware of the frontlight - you may love it or hate it.