Okay I rephrase, if you aren't planning to settle permanently in Saskatchewan, then the nominee program shouldn't be considered.
The pros and cons between the two relate to the above. SNIP shouldn't be an option if you plan to live in Calgary (because of the market or otherwise). It is intended to attract people to the province. As such, they assess your ties to the province before they elect to sponsor you.
The CEC however is federal based and doesn't require intent to settle in any specific province (except Quebec).
From a purely qualification criteria, biggest difference as a student is you can qualify if you work 6 months in Saskatchewan (This can include work before graduation). Under the CEC rules, you must work for 1 year in Canada after graduation.
With regards to processing time, since you can apply earlier to the SNIP, it can process faster. However that depends on how quickly Saskatchewan sponsors you (factors here are how easy you can demonstrate your ties, and other quotas etc.). The actual processing time once you get approved is relatively close to the CEC processing time.
