I own a DeLorme inReach - ~$300 device with a ~$15/month plan. Runs on the Iridium network, unlike Spot's proprietary network. Also, inReach devices are duplex, and can send text messages to friends, family, and SAR teams.
Argument against Globalstar is that it is not a true polar to polar real-time solution like Iridium.
Iridium is the only constellation where you will always find a bird overhead anywhere on the globe (with a ground station relay)
Realistically, Iridium has occasional (~5min) signal gaps likely due to the aging constellation (based on my own use cases developing with a roof mounted antenna)