My employer offered a scholarship in exchange for three years of work as well and I took advantage of it. They also offered as part of their agreement to pay me for 40 hrs/wk plus keeping my benefits and seniority. I had to work the days that I was not in school, but I usually got one day a week off. The hours that I spent in school, doing homework, and going to work was always more than 40 hours if I added them up, but it was still a pretty good deal. For me, it was the only way to go, as I wanted to go to school, but I also needed that full-time paycheck. Working full time and going to school at the same time was not an option for me as I also have a family and other commitments, and let's face it, I need to sleep sometime. It was still rough at times, but I'm glad I did it. I've had people I work with tell me they would never do it because they don't want to be "owned" by our company for three years. But for me, it sort of gave me a feeling of job security, and after all, three years is really not that long. Also, the administrative staff was very helpful and interested in how I was doing after I got my license (hey, they paid for it).
The only down side that I can think of is that if some other opportunity were to come along in the next three years, you might have to pass it up to fulfill your obligation. Also, if for some unforeseen reason you had to relocate or leave your job d/t illness, family matters, etc., this might be a problem. Otherwise, like I said, I think it's a great idea. You might also want to keep in mind that the homework in nursing school is HEAVY (at least it was in the one I went to), and if you have kids to care for or other responsibilities, you really need to be good at time management.
And one last piece of advice -- read your contract carefully!! You need to know exactly what they are offering and what they are expecting of you. You will probably have to maintain a certain GPA (which may be different than what the school of nursing requires). Also, what are the penalties if you should need to leave your job before the three years is over? Are you still liable to repay if they terminate you? Are you guaranteed a certain number of hours per week? Are you guaranteed a certain shift or a certain department? Are there any guarantees at all? And you might what to do a little research and make sure that this a place that you are going to want to work at for three years.
Like I said, for me, this was a golden opportunity. Hopefully it is for you, too. Good luck with whatever you decide to do!