I am on the same boat, but I looked deeply in spreadsheet I noticed one thing is that at the moment who got MR belong to 3131 or 3112 and also I noticed one more thing is that 631 people get mr after sometime, may be I am wrong but it look like this
there may b some correlation. but still its hard to say wht r the factors which speed up the process.
some say its NOC based
some say its ielts based
some say it depends on visa officer
some say it depends on the presentation of ur case
some say its sheer luck
i say 'all of the above'