In principle they are perfect for most things I use OG for, but whenever I go to use them, they always disappoint. Problems include:
Irrational bend radii, depending on control points
Occasionally random start and/or end angles
Tendency for multiple lines to automatically overlap
Over-generous (i.e. non-zero) automatic start and end lengths, distances to bends, control points, etc.
I normally end up reverting to straight-style lines, and manually placing all vertices, which can be very time-consuming. What do you think about the orthogonal line style?
Often I find they work very well. But those times that they don’t are a real pain.
The single sliding handle for coaxing the line to do what you want has definite limits. When it works well it’s quick and easy to adjust a line. But other times there’s just no convincing it to do what is needed.
There needs to be a bit more control.
Update: I just found helpful hint to gain more control. Ctrl-click on the line for a context specific menu pop-up. Adding/deleting midpoints done here. See: Bug: Remove Midpoint button MIA from Line inspector
