Hi, I purchased an used SP2, and it doesn't include OEM touch-pen. I am planning to purchase one, but I am wondering whether I need to pick up an OEM one or one of 3rd party pens. From my research, nib of OEM one cannot be replaced. However, I still would like to purchase OEM one if it is superior over any of 3rd party pens. Since I don't have any experience with the OEM one, I would like to ask for your opinions! If there's any better one or recommended one for SP2 (I heard Wacom Bamboo Feel is good, but it doesn't seem to have any button on it)? I would like to get some pens that have buttons for One Note as OEM one has. Thank you!