I had a 1280x800 tablet, and then picked up a Nook HD+. The higher screen resolution did make a difference. I hadn't noticed any problems before with the 1280x800 screen, but when I used my HD+ for a while and then tried to use my old tablet I realized that the old screen was actually harder to read on, I had to work harder to read small text and see small lines, etc. So that does make a difference.
Since you can get a Nook HD+ new for very cheap now I'd say get that, or look for a cheap high rez tablet. It does make a difference and for me the higher resolution is definitely worth it.