I actually have two Portacolors side by side. One is from 1968 with the delta phosphor, and a 1976 one with a striped phospher layout.

Both have the same dot pitch, but the '68 one has way better resolution. The '76 one seems brighter and sharper, but cannot be viewed up close at all.

I actually prefer that dot-triad phosphor layout. One thing is the striped layout makes the edges of everything look jagged.