I'm not sure a single permanent choice is a good idea- it'll just make everyone wary of playing.
Thaumcraft is a lot more "technological" in nature than AM- you rarely make yourself a magical being, being more reliant on devices, machines, and your knowledge of how to use them- magic as a "mechanical" power, not inner power.
Taint is not a controllable energy- it's destructive and self-destructive. If you get infected with taint, it's more plausible for you to spawn an insane monstrous version of yourself than be able to stay together, as yourself or (more likely) as an ever-screaming pile goo.
Taint and demon blood as a powerful source of soul network energy though...