Well, both, but they are fairly decoupled, just like for 'regular' software developers. Pay is based on willingness to move (and get that sweet, sweet signing b

Well, both, but they are fairly decoupled, just like for 'regular' software developers. Pay is based on willingness to move (and get that sweet, sweet signing bonus), and willingness to negotiate. Essentially: If you are an amazing engineer, you will likely do well everywhere. If you are a 'good' engineer, and you want to stand out, go into QA engineering where you will be relatively better than a lot of people.