Tested on OSSC 1.6 with latest firmware
Line3x works perfect.
Line4x works perfect.
Line5x works perfect
on almost every console I threw at it, but PS1 games via my PS2 on component had weird horizontal lines. (Turns out I had Generic 4:3 off in the Line5x settings, putting that back on makes Line5x work perfect on everything)
Every single mode worked perfectly, all the way up to 5x.
No problems here.
Passthru and Line2x both look fine. I really like the look of Line2x on games like Paper Mario TTYD when I sit a decent distance from the screen.