Imperialus
Explorer
Regarding cyberware and mages:
As I recall, lowering Essence lowers your Magic (Or Resonance). Period. And it rounds down. So yes, cyberware on a mage is a hilariously bad idea. The second you install a single bit of cyber or even bioware on yourself, even if it's just .1 points of Essence lost...BAM. Your Magic/Resonance goes down a full point. You're right regarding the maximum though - hilariously enough, every lost point of essence also lowers your maximum Magic/Resonance. So yeah, you get smacked TWICE for it.
I'd agree that it's a sacrifice, but at the end of the day dropping your softmaxed magic from 5 to 4 due to essence loss costs you 10 BP's.
On the other hand 1 point of essence to play with will get you a pair of rating 3 cybereyes, and a set of rating 3 skillwires. That can ramp up your mages versatility considerably more than throwing one more die in a sorcery test can.