convex vs concave resistor arrays

Convex have five sided terminations for easier or better soldering. The space between terminations is better with convex (generally 0.1mm). Visual checking of soldering is easier with convex, as the solder is not sucked in and hidden from view. Convex is also supposed to self align better, due to the terminators allowing side force from the solder.

I don't know that there are any advantages of concave arrays. The majority seem to be convex these days. I see some references to concave self centering, so maybe they both do.

When manually probing the res network, concave is better, because the probe tip does not slip off or short to adjacent terminals as easily as it does for convex.