Wouldn't the answer always be "it depends on the target, the forces defending the target, and the local topography?"
Sure but some examples can be found . . .
For instance, if I have a large armor contingent as part of my invasion and they are traveling as cargo I might want to land on the opposite side of a major river if it has a few large bridges- dropping BA or infantry to try to seize the bridge so my mechs can rush from LZ to the bridge and across. The river acts as a barrier and limits what sort of counter-attacks that can be launched against your LZ & unloading operations.
Or if you expect it will take X amount of hours to unload most of your combat force, what you plan to use for offense, you will land your force X+1 hours away from your Day 1 objective that has enough of a garrison to respond & challenge your forces. The time could of course be adjusted downward if there were a terrain feature that your attackers could seize for a temporary defensive posture before any of the garrison reached it.
Or for a invasion, do you plan your initial DZ for a Day 1 (or maybe 2) objective of taking a road/rail/port nexus? For example, and unfortunately not having read through the Coalition's invasion of Terra to end the Jihad or how Kerensky invaded when he had his turn but . . . looking at a US map, IMO the ideal place to conduct the initial landings would be to the SE of St Louis along I-44 to Springfield. Send a force up, take St Louis, secure the Missouri & Mississippi crossings, go east for pop & industry or the west is opened up to cross the plains with the mighty rivers at your back. St Louis' little pocket wrapped around by the two big rivers anchors the flanks and gives you a more defensible spacehead that can be expanded as you land more forces at the spaceport in cargo droppers. Only real downside is the 'mountains' and hills west of St Louis that would give opportunity for NOE attacks from ASF, CF and SC on your spacehead.