[ayers]

Something that has not been brought up is what direction are you wanting to pursue. If you are dead set on getting into pen testing then that would add more weight into your decision. If they are both just options for work and you are still trying to sort out where you really want to focus then maybe staying in your current job would be wise.

I would say that it would not hurt to take the phone interview. This doesn't mean you are going to leave your current position. The company could end the process at that point and solve the issue for you. If this is the case, at the very least you gain some more exposure to interviews. If you do get past the phone interview stage and progress to an offer you will have to make the hard decision then. If you did proceed with the phone interview I would take Bigiain's advice and be honest with them. As others have suggested, playing the two companies off each other would not be a good plan since you have already taken the job.