I mostly choose Liang. +1 builder charges seems huge to me. Magnus is often second because I don't see the need to chop forest so early. And certainly not remove features. Though I admit I don't do this as much as I should, I should be removing most of mine by the atomic age and I don't, usually just the ones in the way.
Reyna needs a buff imho. Most of her abilities seem like trash. The only really useful one seems to be the double adjacency of harbors and commercial hubs. As for her initial ability, the difference seems to be too small to really justify getting her first. You'll get more value out of increased builder charges with Liang. She seems okay at popping one border relatively quickly, but after that it seems to get slow again. Her final ability at buying districts with gold is alright, but the game is finished by this point anyways. If you are rolling in gold, you are most likely wining the game already.