Ok, the Sony T series only changes pages with a swipe, not a tap. The other major readers change with swipe or tap. Also most readers have an IR touch screen, so you don't even have to touch the screen, just break the beam by coming close to it, to turn the page.
As for the Kindle Paperwhite, it does not have an IR screen. It has a capacitative touch screen. So that might work better for you. In any case, you shouldn't rest your thumb ON the screen. As for the difference between PW1 and PW2, they have the same resolution, but there are other differences. You can look at the product pages and see which one you like better. I got rid of my PW2 and got a PW1 because I wanted the older firmware. But the newer one has a different screen and is a smidgeon faster.
There are many things I like better about the Kobo. The ease of adding and using my own fonts, the ease of changing the display (margins, etc), and the ease of managing collections with Calibre (a free ebook management program). Also the Kobo Glo is a little smaller and lighter than the PW. (For the PW1, I have added my own font, but I convert my books in Calibre to a larger size font before I load it, otherwise the text is too small (or too large) using the stock kindle font sizes).
As for why have more than one, some of us here at mobileread are a little obsessive. And like to have back ups (what if one breaks, or is out of battery? What if I want a bigger one for at home and a smaller one for my purse?) The reasons are endless! Variety, playing with rooting, etc. [One of my Glo's I opened up and put a 16gb card inside. I did the same to one of my Mini's. The other Mini had a 4gb card so I extended the partition to use the whole card.] I really like the Kobo hardware and firmware, so I actually have 6 of them
