I liked it a lot previously. Now that I have a nook, it is rarely used as a reading device, except for PDFs. I don't dislike it, but it just doesn't work as well. I also pretty much exclusively use my ipad propped on my legs, lap or table when using it. Occasionally if I have to walk around while using it, I of course hold it in one hand.
The nook simple touch is small enough to easily hold it in one or two hands at the right angle for comfortable reading sitting at a table or just walking around. Where as my ipad2 is a little too heavy and large to comfortable do that for too long without some kind of support (flat on a table, using a stand, lap, etc).
The nook ST is just more portable, the longer battery life is nice and I like the eink screen as it is less harsh on my eyes. Another upside is fewer distractions. I am not tempted to hare off and check my email, or a website or play a few launches of angry birds or boot up some other game every 10 minutes. I have ADD...so I know something about the power of distractions
I still use my ipad2 a lot, but I do about 5% of my book reading on it now and I spend 70% of my time in front of electronic devices (not including my work computer or TV at home) on my nook simple touch reading. Probably equal split between my home PC and my ipad2 for the rest of the time.
As a further clarification, I enjoyed reading on my ipad2, but just not as much as on my nook simple touch since I got it.