I agree with karla. CEC is faster, no points, less documents and will even continue processing if your work permit expires and you have to leave.
However, as an accounting clerk, if that is what you have been doing for the last 2 years, you may not qualify to apply under CEC. Accounting clerk, see http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/SearchKeywordResult.aspx?val11=accounting+clerk&val12=0&val13=0&val14=&val15=0&val16=0 is a semi-skilled job, skill level C to be exact and you would need to be of skill level A, B or 0 to qualify. It is also doubtful that you would have qualified under PNP. Does your work permit actually say accounting clerk or does it say something else?
Here is how you read the skill level from the NOC code:
First digit is 0 = Skill type 0 (manager positions)
First digit not 0 but 2 digit is:
* 1 = Skill level A (usually requires university)
* 2 or 3 = Skill level B (often a skilled trade or supervisor positions)
* 4 or 5 = Skill level C (semi-skilled, requires some training)
* 6 = Skill level D (low skilled)
.. so from that, Accounting Clerk NOC=1431 would be skill level C.