It's a bit boring to me but it's not a bad name. I'm kinda neutral about it really.
I live in Australia and pronouce it tee-GN.
Tegan does feel a little dated to me, like mid 90's to mid 00's.
I prefer
Tamsin just because it's more interesting to me than
Tegan.
And as an extra point, I knew a family with 4 girls whose names went together well (I thought):
Tegan,
Brooke,
Jackie and
Rachel.