So, besides from my role playing of my character, if I happen to spare Danse, what changes with the rest of the BoS? Is Maxson's attitude towards the character different? I wouldn't mind getting Danse's perk.

Nope, nothing changes if you spare Danse. Also, you need to spare Danse in order to get his perk.

BoS will shoot at Danse and you if they see you. Killing any named BoS members will turn the faction against you. There's a glitch with Danse that will make him noninteractable once that happens. You can only open his trade menu and can no longer do anything else with him if that happens.

Gameplay-wise, nothing changes if you spare Danse. Their policy still stands, they'll shoot on site if Danse is in your party, and they'll be best buds again if you're not seen together.

Implications-wise: you just had Scribe Haylen openly support a synth over Brotherhood doctrine, and managed to get the Elder himself to doubt his policy: his entire casus belli was synths being tools of war abused by the Institute to destroy mankind, and he just gave mercy to one, believed that one synth can be a good human, possibly a good Brother.

mind blown .gif

You get kick ass power armor, and Danse is KOS to the brotherhood.