Satsleeve is Thuraya exactly the same service and sim as there XT Lite / XT Pro model . External Antenna doesn't boost signal .Just places antenna in view to the Satetite for uninterrupted service. Thuraya Xt lite ,Isatphone and Retired TelitsCant comment on Optus.
Dont know if this applies or not but have a sat sleeve with pivotel and cant really fault its value for money
Kept my normal number and invested in an external aerial than can be mounted on the roof in case of poor coverage
Not perfect but pretty good for occasional use
I am on a Telstra $35 per month Iridium plan and it's a standard 0419 mobile number on mine.https://www.telstra.com.au/coverage-networks/mobile-satellite
Not as good as Pivotel as its not got a normal mobile no, bit more expensive to use but ill be connecting with telstra next time as pivotel is now up to $50 a month which for me is too much seeing its only there for emergencies.