Larger Firm or Stay Put

I am 25 and am finishing up my first year as a staff accountant at a small firm (15 people total) in Kansas City. Once I hit the experience requirement I will have my CPA. Most of what I have done this year is in tax with a small amount in audit. They say I am doing a really great job and have bumped my salary up to 60K for next year. Career wise I want to be a partner one day or potentially branch off into a management or finance position in the private sector. I know that is pretty broad, but I'm still young and inexperienced. I'll stay at my current firm in 2017, but what do you think would set me up for the greatest success down the line? I know a lot of people in the industry boast about how the Big 4 can open a lot of doors, but I've also heard that it can be pretty miserable.  Where I am at the most I had to work in one week was 60 hours, summer was 40 a week, and it looks like Nov and Dec are going to be the slowest months ever (minimal work for me to do but still need to be at the office). Primarily our clients are real estate investors. I don't think it would be all that helpful to go back to school for a MAcc since I'm already working and have an MBA. Any thoughts?