Hi,
1. 3 years PGWP (by ONLY studying 14 months, that too out of that 4 months internship)
2. 8-12 MONTHS PGWP (mostly 12, if you do co-op)
3. 2 years PG cert/diploma will give 3 years PGWP, and Two 1 year courses will give ONLY 2 years PGWP.
Now, strictly talking in terms of getting a PR: by working ANY job for 6 months, and then getting ANY full time job offer in Sask. province..which is the easiest way to get PR, You follow ANY of the 3 options, doesn't matter. But obviously.. studying 2 separate 1 year courses and getting only 2 years PGWP will be foolishness, when by studying a combined 2 years PG programme, you can get 3 years PGWP! Anyways, people (and even I) prefer for getting a 3 years PGWP, because that will give us a hell lot of time at our disposal, and you can in a relaxed way, find a job..do it..and then apply for PNP, whereas in getting 1 year PGWP, you will have to rush everything.. rush to Sask. province.. complete your 960 hours/ 6 months as soon as you can, find a full time permanent job offer and then apply for PNP. Well, 1 year is ALSO more than enough time to get PNP nomination, but a 3 years PGWP at your hand, you will not have to rush..and you can look for actual skilled jobs in your field of study. That's the ONLY difference.
Infact, 1 year PGWP is more than enough, if you can find a full time permanent job, in your area of study in Nova Scotia province, and work there for just 3 months (instead of 6 in most of other provinces), you can then apply for PNP nomination which takes upto 2 months. So, in Nova Scotia you can get your PNP nomination in as little as 4-5 months, instead of usual 9-11 months in other provinces. To know more about Nova Scotia PNP check my previous reply on this post:
http://www.canadavisa.com/canada-immigration-discussion-board/i-dont-understand-the-immigration-process-for-international-graduates-t99800.0.html;msg1358952#msg1358952
In my personal opinion, No matter what you plan to do,it's always best to try and secure your PR within the allotted PGWP period(which you can use only once in a lifetime)... and then look for whatever you want to pursue/study/other work of your choice etc. Once you get the PR.. life will be much better...
You can even pursue higher studies at cheaper(for locals) tuition fees.
Saying this, if you are talented, have very good profile..and are genuinely interested in building your career, then you can start building up your profile, apply for a good MBA/ choice of your course in a reputed University in Canada, get a skilled job (which is tough)..which will anyways..get you a PR automatically under CEC or PNPs, like Enfield prefers. So, it's really your choice.
As for me, I'm not at all academically inclined, got 2nd class/ poor marks..and cannot afford to spend time or money on a 2 years PG cert. course. So, I'll be opting for a 1 year PG cert/diploma in any of these colleges and then get a 1 year PGWP, and move to Sask. province (provided.. if I get the visa.. LOL)!