I don't own a sony so can not give an opinion on that. But rooting nook touch is very easy (at least for me but I am tech enthuast so it might not be so for others).
I just followed the instructions from here
http://forum.xda-developers.com/show....php?t=1343143
and that was it. If you use the image from the above link it will install google market and amazon android market for you. After that you can download all compatible apps like coolreader( the best non drm reader for Android)
I read somewhere that coolreader supports nook touch better with the ability for full page refresh or partial page refresh settings compared to sony but as its updated regularly that might have changed and now might have better support for sony as well.