Thanks for sharing your results, oha. Author of "PixelOperator8.ttf" has clearly put some effort into his font, so that at 8 px height text looks as good as it possibly ever can, probably. (See some comparisons below.) I just hope these 8 px are not modern display pixels, but something larger.
Your link is to outdated (and named differently) version, which produces "somewhat" inferior result. Here is better link.
Below is "screenshot" (produced in a way similar to what you did:
say $im-> getscanline( y => $_, type => 'index' )
=~ tr/\0\1/O /r
for 0 .. $im-> getheight - 1;
, for "paletted" image 80x60, similar to what I did :) ), for these test subjects:
'10714/8bitOperatorPlus8-Regular.ttf', # Abomination from wrong link
'pixel_operator/PixelOperator8.ttf', # Correct version
'ucs-fonts/6x12.bdf', # 'Fixed', from my answer above
+
'uw-ttyp0-1.3/genbdf/t0-12-uni.bdf', # http://people.mpi-inf.mpg.de/
+~uwe/misc/uw-ttyp0/
'gohufont-2.1/gohufont-uni-11.pcf', # http://font.gohu.org/
OOO OO OO O
O O O O O O
O OO OO OO OO O O OO OOO O O OOO OO
OO O O O O O O O O O O O OOO O O
O OOOOO O O OOO O O OOO O O O O OO O
O OO OO O OO O OOO OOO OOO OO O
OO
OOOOO OOO OOO O
O O O O O
+ O
O OOO OOO O OO OOO O O OOO OOOO O OO OOO
+ OOOO
OOO O O O O O O O O O O O O O O O
+ O
O OOOOOOOO OO OOOOO O O OOOO O O OO O OOO
+ O
O O O O O O O O O OOOO O O O
+ O
O OOO OOO O OOO O OOOO O O OOO OOOO
+ OOO
OOO
O O
OOOOO O O OOO O
O O O OO O
O OOO O OO OOO O O OOO OOO O O O OOOO OOOOO
OOOO O O OO O O O O O O O O O O O O O
O OOO O OOOO O O OOOO O O O O O OOO O
O O O O O O O O O O O OO O O O
O OOOO O OOO O OOOO OOOO OOO OOOO OO
O O
O OOO O
OOOO O O OOO O
O O O O O
O OO OO OOOO OO O O OO OOO O OO OOO OOOO
OOO O O O O O O O O O O O O OO O O
O OOOO O OOOO O O OOO O O OO O OO O
O O O O O O O O O O O OO O OO O
O O O O O O O O OOOO O O O O
O OO OO O OOO O OOO O OOO OOO OO
O O O
OOO
OOOOO O O
O O O OOO O O
O O O O O
OOOO OOO O OO OOO O O OOO OOOO O OO OOO OOOO
O O O O OO O O O O O O O O O O O O O
O O OOO O OOOOO O O OOOO O O OO O OOO O
O O O O O O O O O O OO OOOO O O
O OOOO O OOOO O OOOO OO O OOOO OO
O
OOO