Pretenders: Rainbow vs SC

[Finalgenesis]

I've noticed that I've only used awake/sleeping rainbow mage (Usually humans, sometimes master lich/ ghost king) and never SCs. I value the magic diversity, crafting flexibility, summoning options and the immense gem income from site searchs from a rainbow much too highly to ever use anything but a rainbow. Spells like contact naiad, stream from hades, ether lord, draconians, troll court...etc are just amazing mid-late game for good diversification.

It seems that most SC require either some items or Dom 9-10 to help out (with exception to Gorgon SC maybe), and I can't seem to shell out the points to do that. It seems to be a waste to dump so much points into a SC who gets weaker in enemy dom, whereas a rainbow can give you a huge exponential boost to gem income and summon multiple thug/SC chasis later on in addition to mad crafting and summoning. I have a checklist of summons and artifacts I HAVE to have to sleep at night (dwarf hammer, boots of quickness, boots of flight...etc).

Of course I've never used SC pretenders before, and as I understand it, it is really for is early game expansion and early-mid province defense? Any players who use SC pretender a lot can enlighten me why anyone would use SC over rainbow generally? (I can see SC for certain nations needing a boost to early expansion or heavy bless, but not general usage)