I would definitely go for U. Michigan if I were not accepted by U. Chicago. Ranking in stats area, job placement, preparation for PhD, TA-opportunity, cost of living, Michigan beats UCLA in all of them. Of course, it would nice to live in Cali with sunshine all year long and LA is a paradise
I am not trying to say it would be a terrible mistake to choose Michigan over UCLA. It depends on what u want after masters. My cousin (international student with US undergrad degree) actually graduated from UCLA's stats masters program last Aug.and his experience was that masters students do not get much or none attention from Profs or the dept. And it's quite a small dept with heavy focus on computational statistics if that interests you. He is now doing another masters in fin. math at NYU simply b/c he cannot land a job after graduation. He told me he regrets a lot for the tuition and high cost of living paid for 2 years' UCLA life lol.
Hope that helps.