SM command squads are certainly fun to fiddle with, but their biggest drawbacks are the fact that you have to take a captain and the fact that they are very
CC focused.
The best way to run them would be on bikes. That toughness bonus marries very well with
FNP. Then the storm shield counters the
FNP ignoring stuff. I love this rig.
captain - bike, relic blade, storm shield
apothecary - bike
company champion - bike
veteran - bike, relic blade, storm shield
veteran - bike, power fist, storm shield
veteran - bike, power fist, storm shield
I might have just made an illegal unit here, don't rip my head off if I did so

. I don't have my dex handy and I haven't really built a ton of command squads. I forget if the apothecary can buy a shield and/or a special
CC weapon. If so, buy em if not that unit is quick, choppy and hard.
I don't think I'd run them on foot unless it was a story driven moment. On foot with the same equipment its more efficient just to buy an assault terminator unit and join it with your choice of
HQ. Either deep striking or riding in a land raider.