I use nothing but eco comm. Beamlaser + e cell, then pure carreps nanos.
The only time you should ever morph your commander is when you suddenly find yourself with more resources than you can spend: You just lost your factory, nanos, or cons, your expansion just started to pay off, you just got a huge reclaim boon (Say, his enemy comm), your just finished your supergeo morph and now you have heaps of overdrive, you just got metal from a /take etc etc. With proper planning this will happen less, but it still happens.
When it does, morph your comm. If you're playing like this, you're only using the morph as free BP. Since when you are in this situation, all you -need- is more BP, you might as well spend the temporary free BP from the morph on securing more, long-term BP.
A BP comm is also incredibly powerful, he can make any weapon for any purpose almost instantly, and only when he needs it. You can win any and all comm wars. If the enemy has an LLT or defenders, just build your own LLT within range of them. Put your comm on repeat if need be, to make sure the nanoframe goes down and waste defender shots. It will build faster than their DPS and then repair enough to kill them. If you have radar coverage, you'll always see an army moving towards you and be able to insta-build a field of turrets before they arrive.
But, every comm, even a BP comm is metal inefficient, which is why you should only morph when excessing. Think of it like making puppies, they convert reclaim very ineffeciently into more puppies, and you often lose large amounts of them, but they do it so quickly and with no BP costs so that's why you make them. Puppies are bad, yes, but free puppies are good. Comm morphs are the same.
