Proiteus asked me this question about Marbo yesterday on Librarium Online:
My mech army is now complete and giving me lots of victories except for the Leman Russ that was plagued with bad luck and as a result has been removed and replaced with a Banewolf that has done so much better.
Anyway with all 3 fast attack choices filled I had to drop my scout sentinels at 1750 which left me with enough points to take Marbo after buying a Astropath.
My only concern is how effective will he’ll be, being the only infantry model in my army (unless a chimera blows up). As memory serves I can remember you featured marbo in your own fully mechanized lists so tell me…
In all your games has Marbo been more of a valuable saboteur or just an easy kill point?
Cause if not I’ll take a Griffon Mortar.
I don't see any difference in Marbo's usefullness based on whether he's included in a Mech army or a hybrid/foot force. Marbo's fairly self-contained in his role as a spoiler/distraction.
But his effectiveness does depend on the point level of the battle. From about 750 to 1500 points, he's great! As he'll do enough damage when he comes on to really hurt and require enough attention afterward to tie up a decent number of enemy units.
But above 1500, his usefulness starts to wane as the amount of damage he can do (as a percentage of the enemy force) declines and the ability of the enemy to kill him in a turn with an unengaged unit rises (due to there being more troops on the field). Until, at 2000 points, I consider him to be little more than a free kill point.