I have a MAcc, so here is how I look at the programs.
MST: If you want to pursue a career in tax, then this should be a no-brainer. If you don't want a career in tax, why bother?
MAcc: I obtained a MAcc as part of a career change. My undergrad had nothing to do with business nor accounting. Based on my experience and the curriculum, I think a MAcc is a great degree for someone who is new to accounting, or for someone would has a business-related undergrad (finance, economics, etc) but would like a graduate degree with a focus on accounting.
MS: If I had an accounting undergrad, I would have pursued a MS instead of a MAcc. From reviewing the curriculum, the MS programs I saw appeared to be built with the idea that the student already had an accounting undergrad but would like to broaden their knowledge and perhaps specialize in a particular area of accounting. For an example: Forensic Accounting.
The reality is that all of these degrees are viewed with a level of prestige. I don't think that the MAcc should have the amount of prestige that it receives, especially for people like me, but the reality is that people view graduate degrees more favorably than undergraduate degrees. At the end of the day, the decision to take a certain path should be done with a goal in mind.
As for the GMAT, it doesn't matter. The program I attended didn't require the GMAT. IMO: I think the GMAT is a huge waste of time unless one is hoping to get an MBA from a Top 20 B-School. I took it twice before giving up, and I don't feel that it impacted me negatively. In fact, I view the decision to throw in the towel as one of the best decisions that I've made in my life.
FAR - 80
Courage is being scared to death, but saddling up anyway.
-John Wayne