Hi,
As I said... most Canadian universities need B grade or minimum 60% in final 2 years of B.tech degree for students from India, Pakistan, Bangladesh, Nigeria etc. and an IELTS score of 6.5 overall (with no bands less than 6)(some may require IELTS score of overall 7) for applying to engineering Master degrees. They DO NOT require GRE. The higher your B.tech scores are... more your chances of getting admission (as it is one of most important factors for getting admission to Master degree programs at Canadian universities). So, your selection will be primarily based on the marks of your B.Tech degree. The research based degrees (MaSc's) are usually much more competitive, where one generally needs to show some knack for research (like published papers) and selected students usually get partial or full funding. You will mention this 1 year PG certificate as an added qualification... an added Canadian certificate... on your resume.. will put more weight... particularly if it's related to your field of study - CS/related fields. Not to mention..you just need to do a 1 year M.Eng program after that..to be eligible for a 3 years PGWP, while others with you passing out from the 1 year M.Eng program will only be eligible for a 1 year PGWP. Saying this, doesn't mean that you should be aiming only for a 1 year M.Eng program...but you should also try your best for getting into M.S (research based program with funding) or a better M.Eng program with industrial co-op/internship option (very good for getting valuable Canadian work ex.... even if the M.Eng is longer than 1 year)... both will be a very good move for your career.
The question you are asking me is of technical nature. Had this been some generic management course, I could have honestly advised you... One of the reasons you won't find many discussing these PG cert. technical courses are..simple..as I mentioned..are that valued or pursued.. Most engineers prefer to do M. Eng/ MaSc. What I can tell you is... since you are a CS engineer... go through the "Course contents" of all these technical PG courses you shortlisted.. and compare the subjects/course contents..and see which might suit you best.. keeping in mind your CS engineering background and your long term goals to pursue Masters... You can do it best.... and you will know which subjects /branch (eg. Wireless networking or Database development) will be better for you..suit your profile more...If you have no idea about them.. Google them! You will eventually figure out the best course for you. And regarding colleges... although most are similar.. I've honestly no idea which technical course is better or worse.. but a college like GBC, right in the heart of Toronto city..is a reputed college.... but the again..course content matters.
Hope it helps.
Best of Luck.
***All opinions expressed are purely personal, and pieces of information mentioned are to the best of my knowledge... You should consult other sources too.