I have had the ATT version of the Note for almost a month now, so I'll take a stab at your questions:
1) It is excellent as an ereader. I don't think I have used my Kindle since I got the Note. It's 5.3" screen is close in size to the 6" screen in the Kindle. I use white text on a black background and this seems pretty easy on the eyes. However I rarely read for more than 30 minutes at a time (and I didn't with the Kindle either). I most frequently read while eating and simply lay it on the table and change pages with one finger. If I am holding it in one hand, I typically change pages with a finger of the other hand. The biggest advantage over the Kindle is that the Note fits in my back pocket and it is always with me versus carrying a second device.
2) It seems as good as my previous phone as a phone. I'll admit I don't make many phone calls and rarely when I am in a moving vehicle, which is when I suspect most dropped calls occur.
3) I played with the stylus a little the first day and then haven't pulled it out since. Since I never had a stylus before, I haven't adjusted to it being available now. I would say my primary uses for the Note are:
A) Read books and fanfiction (Highly recommend the fanfiction app in the google store, if you like fanfiction)
B) Watch videos while on the treadmill at the gym (replacing my old 7" tablet. It had a bigger screen, but much poorer picture quality and its battery was dying.)
C) Listen to audiobooks in the car (I love the audible.com app)
D) Check email and occasional lite web browsing when I am out and about.
E) Phone calls.
4) I definitely think it was worth it to me. I consolidated from three devices (phone, Kindle, 7" tablet for videos at the gym) to one device that is always with me.
5) My phone is stock. I will probably upgrade to Ice Cream when it becomes available from ATT and has been out for a while to verify it doesn't create problems. Truthfully, I have never seen the point of rooting and modding phones unless it adds something you really need and the phone can't currently do. But this phone already does everything I want without wasting my time doing those things.
Hope this helps,