I hate onscreen buttons. They are annoying and make the whole screen look ugly. When they disappear into three dots like in the camera app and you have to pop them back up, its all a waste of time and screen. Samsung, LG, and HTC realize how stupid they are so they have not embraced them. Google needs to learn some humility and know when to back down when they've made a mistake. Microsoft allows for microSD cards now in WP8, completely changing their tune about it since WP7. Google is still defying the market, sticking with onscreen buttons and no expansion on their nexus phones. MicroSDs are cheap and far cheaper than getting a higher GB model, if you can even find a higher GB model that is.
I like that HTC reduced the number of buttons and made them smaller. They are still big enough to hit easily, but aren't hugging the corners like Samsung or LG phones, which are very easily to press by accident. Less buttons also means less accidents. One of the great things about the iPhone's single home button is that you always know where it is and its easy to press without looking for it. Press once for home, double press for recent apps, press again on home to go to first page or go to search, hold for Siri. It's easier for me than having to remember the constantly changing button order on phones, having to distinguish between them, or pressing the wrong one by accident. HTC is simplifying the buttons for the better. I also like the HTC logo in between the two buttons.