First of all, the inland process (Spouse or Common-law IN Canada) typically takes longer to finalize than "outland" (Family Class: Spouses, . . ., etc.) and because your spouse doesn't have documented temporary status in Canada, the application will likely be sent to a local CIC office for processing - before first stage approval (which gives an applicant the right to apply for a temporary status document like a work permit). Depending on where you live, that can delay processing for months/years because offices in areas where there's a high influx of immigrants have tons of applications to deal with, and their backlog can be in excess of a year. The problem with that is that the inland applicant is required to be in Canada, living with their partner, in order to be approved for PR. Any applicant who leaves Canada risks being refused re-entry - so there's no way for an applicant in this situation to easily GET documented temporary status - potentially putting them in "limbo" for months on end, with the risk of being required to leave Canada hanging over their heads the entire time. And if they do leave Canada, and are refused re-entry, the inland ap is forfeited. So, applying inland without having legal temporary status (even though it's allowed) can back you into a corner in many ways. In addition, the inland process has no right of appeal.
That said, everyone is entitled to apply "outland", which only means that the application is processed at the overseas visa office that represents the applicant's country of birth/permanent residence. There is no residency requirement with an outland ap - the applicant can be living/visiting anywhere and it will not affect the process. Outland timelines are typically much faster via this route - even without the complication of delays due to lack of documented temporary status when an ap is being processed within Canada - but there are some inconveniences associated with filing outland when an applicant wants to stay in Canada during processing. Most of these "complications" center around the fact that 1) the applicant must still maintain temporary status in Canada in order to stay, 2) if an interview is required for the PR ap, it will be held at the overseas visa office (which requires travel and no guarantee of re-entry to Canada), and 3) outland processing requires delivery of the passport to the overseas visa office in order to receive the Confirmation of PR and ability to land. Some countries don't allow posting of passports over international borders - and it's not always advisable for a foreign national to be in Canada without their passport in hand. Also, (currently) the landing interview takes place at a Canadian port of entry (this may change soon), meaning the applicant must leave Canada and re-enter in order to activate permanent status after receiving the COPR. That could be problematic if a foreign national applicant is not able to enter the US, although some have reported being allowed to, basically, make a U-turn through US customs in order to come back to Canada and land.
In the end it's about personal preference and which process you think best fits your situation - but it's good to be informed of the differences and drawbacks to both processes so you know what you're getting into before you make that decision. I wouldn't recommend the inland process simply because you say your spouse doesn't have documented visitor status. Where is he from and how long has he been in Canada?
