While it took some getting used to, I actually found that I was sleeping much better. In fact, I since figured out that sleeping without the second pillow often leaves me more vulnerable to the migraine headaches that used to plague me. At this point in my life, should I sleep with only one pillow, I need to fold it in half (which is also not comfortable) or wake up the next morning with an aching head (as opposed to an aching neck).
Over a year ago, I got a Sealy Half-and-Half pillow (half quilted, half memory foam). Since then, I've been using it as my top pillow with a regular extra-firm for the bottom one. Recently, my extra-firm started moving more towards the rock-like category no matter how I fluffed it. As we had a spare Half-and-Half pillow, I switched them out.
Unfortunately, switching to a newer pillow is always uncomfortable for the first couple of weeks, as the newer pillow is invariably fluffier and thicker than the old one. Basically, my head is a bit too far up off the bed, and it's making for some restless nights. The plus side is that I've had some great dreams lately and have been able to better remember them since I keep waking up through the night.
I'll get used to it, but right now it's just a pain in the neck.