TL;DR at the bottom.
A decade ago I was in my freshman year at university working towards my bachelor's degree when I applied for one of these jobs that offered to "pay for my degree." I was racking up debt, so this seemed like a great opportunity. I was offered an interview, but it was during the final exam period in my spring semester. I talked to my professors, told them what an amazing opportunity this was, and they were willing to be flexible and let me take my finals early. I made my interview and got the job. This job was in another city from my current school, but "no problem" I thought. I just moved and started working on transferring my credits.
A month into working, I went to HR to apply for help paying for school in the subsequent fall semester. When I talked to the same person I had interviewed with (who I had told about my interest in this tuition assistance program) they only then informed me about the stipulations:
1) It was tuition reimbursement, not tuition payment. This meant I had to float the company thousands of dollars until the end of the semester. Then they'd pay for any of the classes for which I received a B- or higher. That kind of liquidity was hard to achieve given my income ($12.50/hour).
2) It was only available to employees who had been there for 6 months, so I wasn't even eligible to apply until another semester away from school.
3) They would only pay for a degree in something relevant to the company's interests. Due to the nature of our work, this meant computer science or something that'd put me in HR.
4) It would only cover $4000/semester, which was about enough to cover community college full time or state school part time.
5) It was only available to people working full time, meaning I could only go to school part time anyway. This meant that the remaining 3 years of my degree program would've taken about 6 years of my life.
6) If I left the company within 5 years of reimbursement, I would have to pay every penny back to the company. I would be indebted for half a decade after graduation. So all together this meant I'd be working at this company for the next 11 years.
7) If I was written up for any infraction at work, I wouldn't be eligible for the program.
Each stipulation on its own sounded reasonable, and I was a naive 19 year old, so I went along. After all, I had been taught that good things come to those who work hard, and I was willing to work hard. In the subsequent semester I took off from school, I picked up about 15 hours/week of overtime (on top of 40 hours/week) and was promoted twice. The OT helped me build up my nest egg to pay for classes up front.
In the following spring semester, I started a community college class with the goal of earning my degree "the right way." I wanted to ease back into school, and did well balancing my time (draining as it was). After my first semester, I received my check to help pay for my class. Woo!
For the next fall semester I signed up for three classes. It was a full load, but if I "put the work in" I could make it happen. And I was going to school for free, while meeting all of the expectations at work. I was doing it "the right way." Until I wasn't. You see, I used my phone at work to text my brother. Not about anything damaging to the company, not in front of a customer, and not something I hadn't done 1000 times in the previous 8 months while working at the company. The same 8 months in which I had exceeded every performance metric they had and earned multiple promotions and raises. Nevertheless, the company caught my violation a month into my second semester, and wrote me up. I was out thousands of dollars for tuition, and had just wasted over a year of my young adult life on this opportunity. My nest egg was gone, my bank account empty, and I had 12 credit hours to show for a year and a half's worth of work and then some.
At that point in my life, I had a positive role model that broke down my options in a way that made sense: even assuming that the company hadn't deliberately screwed me, moving through school at a snail's pace on their terms wasn't worth the delay. What they paid, plus the tuition assistance program, totaled about $30,000/year. That amount of money sounded nice to have in hand, especially at that age, but I needed to consider that the degree I was pursuing was going to afford me at least twice that salary on the open market. That meant that every year I wasn't finished with my degree was costing me a similar $30,000/year. That'd make for $90,000 in lost earnings by delaying my education an extra 3 years. Not to mention I'd be locked in at the company an extra 5 years after graduation, meaning they'd have no incentive to pay me a competitive salary. The company wouldn't have to offer competitive salaries if they were competing with no one, meaning I'd be losing even more money.
TL;DR: Don't go out your way to work for a company that offers "tuition assistance" or "corporate scholarships." They wouldn't offer you money unless it was benefiting them financially in the long term, and in the long term they're going to get their value out of you. Not to mention, they'll probably find a way to screw you and not pay you at all.