The HD is a good reader. My only problem with it (now that I have the KA1) is that it seems soooo small now
(6" really doesn't work for me anymore). The screen is no more prone to issues than any other e-ink device. NOTE: a case may help, but IMHO it's twisting that breaks most screens and that's from being in a bag or purse etc with other stuff and (again IMHO) a case does very little to protect it from twisting (especially the bigger devices). If you're traveling around with it you need something solid to keep it in (personally I have a wooden box for when I'm traveling with it). Don't bother with screen protector. It could mess with the IR sensor if it's too thick and scratches on the screen aren't something that happens except in really, really rare conditions.
No idea what current prices are, but I don't think you'll regret the HD if you're happy with whatever price you pay for it.