The reviews I've seen indicate the Inmarsat phone would have better sound quality and better speed for internet (doesn't sound like you were planning on using that). I've never heard anything bad about either. Canadasatellite.ca indicates the price would be CAD$482 for a month with 80 minutes. That includes CAD$135 in rental insurance and $20 return shipping. Does that save you anything?
Thank you @ Brian G. Yes, it saves me about CAD$50, but I have read very poor reviews about Canadasatellite.ca, that they were not very professional and don't deal with complaints particularly well.
While money is ALWAYS important, since this is my first foray into satellite phones, and know very little, my main concern is
reliability and ease of use. Good customer service is also very important as I need help to learn how to use this thing when I get it. I don't know anything about the store that I think I will be renting from (roadpost.ca) but they don't have poor reviews, and so far, their email customer service has been clear and prompt.
I am looking into the Inmarsat satellite now. I was told that "Iridium has the best coverage" but I honestly did not look into Inmarsat.
I actually wanted to rent the Iridium Go!, which is a satellite Wi-Fi hotspot, but they did not rent it. Only satellite phones. I did not want to buy anything until I tried it via rental.
Update:
Here's what I found re coverage (not sure how up-to-date or accurate this is):
IRIDIUM
Complete worldwide coverage makes this service an ideal choice for hikers, adventurers and explorers. The equipment is robust, waterproof and perfect for use in any emergency.
TRULY GLOBAL COVERAGE, including polar regions
Satellites pass across all areas of the globe, so you have the best possible chance of getting a signal.
INMARSAT
Inmarsat gives you the best signal strength and lowest chance of dropped calls. It's the ideal portable satellite phone for marine and leisure sailors. Great on land as long as you are not too far north or south.
NEAR-GLOBAL COVERAGE, except polar regions over approx 70 degrees North or South
Satellites are always in the same fixed positions in the sky, so great if you happen to have clear visibility to the satellite, but not so great if you haven't!