velvetsun--
What you're experiencing with your Kobo Aura HD is not at all normal. I have both an Aura HD and a Kindle PW2--and don't notice a difference in how each of them operates. When I tested the page turns on each of them side by side, the Kindle seemed to be just a hair faster--but not something I would notice if they weren't right next to each other.
You might try a basic reset of your Aura HD to see if that helps. If not you might want to go a step further and do a full factory reset--but be warned if you do this, you'll lose everything on your Kobo and have to re-register the device to your account.
Here's a link to Kobo's website that discusses the basic and factory resets:
http://www.kobo.com/help/en-US/artic...r-kobo-ereader
Good luck!