I have been using the Poetic Slimline on the Note (in red, if that matters) for a couple of months as well. It is a very nice case and I have no problems to report regarding the S-Pen. However, there are a few things related to the lid that are starting to annoy me and have me investigating alternatives.
1. The magnets that are supposed to hold the lid closed are not strong enough. If I hold the tablet as if it were a notebook with the spine (the side with the capacitive buttons) resting on my palm and start walking, the lid will open by itself after a few steps. To prevent this, I now hold it on the opposite side so that my palm is holding the lid closed. If I hold the tablet by the edges with the lid facing down, the lid will not stay closed. I also own a Nexus 7 in a Poetic Slimline case and that one has no problems with the lid staying closed. I think the size of the Note may be too much for the magnets.
2. I am not sure I can blame this one entirely on the case, but I have observed some problems with inadvertent screen activation. Because the lid hinge is made of the same leather-like material, it is flexible and allows the lid to slide up or down along the screen while closed. If you slide the lid up by about 5mm, the screen will turn on even though the lid is closed. For me this happens most often when I carry the tablet (in the case) inside a backpack. Similarly, the lid is thin and flexible enough that the home button is easily pressed. There have been several occasions when I have pulled the tablet out of my backpack to find it on and with the S-Voice user agreement on the screen (I don't use S-Voice so have never set it up).
3. This is a minor aesthetic issue, but the tri-fold elements on the lid tend to not remain flush with the screen when closed; it is probably just the nature of tri-fold covers. Personally, I would prefer a single piece lid that could be folded back, even if that would mean losing the ability for the case to serve as a stand.
If it weren't for the items above I would be completely happy with the case. In fact, I love the Nexus 7 version of it. I just think the lid material and/or the closure magnets are too weak for the increased screen size of the Note.