Low contractor pay: not unique to Foxhole, that's just the government contracting business, but beware joining them as a subcontractor instead of the prime on the contract. There is a LOT of money being scraped off the top of your salary before it ever gets to you.
Awful insurance that covers little, plus the absolute mess of submitting bills for reimbursement from a company-funded HRA account was almost not worth the trouble.
Little room for advancement - they pay a lot of lip service about outstanding service to the customer, but at the end of the year you're probably just going to get a small raise with no hope of promotion no matter what you do.