I may be able to offer insight into a couple PGR rated MA programs. I was rejected from Tufts, and accepted by Brandeis and Northern Illinois. I don't have any first-hand info about Tufts, but from what I understand, admitted students should expect ~50% funding at the most. The funding package that I received from Brandeis included 50% tuition remission and an assistantship for a single semester. I confirmed with the department that there is no further funding. The need-based funding that the graduate school offers through fafsa is included in the partial remission. The weird thing is that this year, the admission letter called this a "merit-based" scholarship. However, in previous years it has been billed as "25% need-based and 25% merit-based" scholarship. When I discovered this, I found their liberal use of "merit-based" misleading, since I mistakenly assumed that there would also be need-based funds available for my education. The program is technically a single year, but nearly all students extend it to 1.5 or 2 years. The extension fee is around $5,000. The assistantships are guaranteed to every student for a single semester. Depending on undergrad enrollment in philosophy, most students TA for more than one semester. This year the pay was $3,200 a semester. All together, I would have paid at least $22,000 for an education at Brandeis. I was told that Brandeis simply doesn't have a large enough undergraduate enrollment to offer more funding to graduate students. Most grad students in philosophy take out loans to fund themselves. IMO you are paying for an excellent education in an academically lively city--e.g. Brandeis students often take classes at Tufts and Harvard. So I can see how some students could incur the costs to go there.
I don't know much about UWM, but it sounds similar to NIU. NIU offers excellent funding I think. Most students enjoy full tuition remission for their first year. Tuition for the second year is still less expensive than most schools. The department also offers ~five graduate teaching assistantships. The contract lasts for a year and is renewable, pending academic progress, etc. The pay this year is around $12,000. Compared to the TAship at Brandeis, not only is the GTA-ship at NIU twice as long, it also pays twice as much. That said, I've heard that the department at Brandeis offers full funding to one or two exceptional students each year. I think they try to keep this on the hush-hush, so you may be able to negotiate. I was promptly shot down when I tried.
At the end of the day, each student has their own utility function. Having visited with grad students at NIU, Brandeis, and even a few MAPHers at UChicago, I could totally understand why a student might choose to incur debt and be a part of an awesome philosophical community, or choose to study in the not-so-exciting town of DeKalb alongside really excellent faculty and peers.
I hope this gives you a picture of two very different funding offers. Let me know if my limited perspective can be of any more use.