On pixel density -
http://androidforums.com/android-lounge/330462-higher-rez-screens-why-not.html#post2653285
On comparing two other model phone displays -
http://androidforums.com/htc-evo-4g/110482-evo-4g-vs-epic-4g-25.html#post2146012
On the danger of making blanket comparison statements -
http://androidforums.com/android-lounge/274897-samoled-vs-slcd-vs-qhd-vs-retina-display.html
On what the problem is -
http://androidforums.com/htc-evo-3d/303494-how-does-qhd-compare-super-amoled.html#post2536229
SLCD - despite the blogs and all the "super" nonsense - is a brand of LCD supply. The Evo 3D doesn't use an SLCD panel, it uses one made by Sharp. The technologies are different for these suppliers, so there will be differences in color ranges, color tendencies and viewing angles.
SAMOLED+ --- deeper blacks, tendency to black crush, tendency to oversaturate
Sharp LCD --- tendency to not oversaturate or black crush, full weaknesses won't be known until we see them in our market (Sharp has been making Android phones not available in the US/Europe for some time), but assured it will have weaknesses
qHD is just a resolution spec - exists now on LCDs, highly likely will exist in near future on SAMOLED+.
We all see correct color properly - it looks like the real world. We all see wrong colors differently, so until we get correct color, choosing either is subjective and must be made by the individual - there's no right or wrong answer.
Hope this helps.
PS - Blogs today claim that LCDs come in the various forms of: LCD, Super LCD aka SLCD, and TFT-LCD. That's a display of maximum ignorance on their part, and they're successfully added FUD to the consumer equation. All LCDs you've seen since beyond early calculators are TFT-LCDs. Super TFT came out in '96 and is better known as IPS (Hitachi and LG TVs, Apple displays). SLCD is a company made up of Samsung and Sony, their panels range in quality types, they're not all the same, and appear in Samsung HDTVs, Sony Bravia HDTVs, and many phones.
The blog FUD has left people thinking that comparing S/AMOLED/+ vs SLCD is Samsung vs. Other - truth is, those are comparisons of different Samsung technologies.
Introduction of more Sharp panels into our market will be interesting -- they could be worse, same or better than SLCD panels we've seen: too early to tell. (LG Optimus 3D uses Sharp methods for 3D - could be a Sharp 800x480 panel or could be an LG panel using tech licensed from Sharp - dunno for certain.)