I recently used the InReach when sailing across the Tasman Sea.
1. It worked flawlessly for tracking as displayed on the share.delorme site
2. It's SMS text function also worked flawlessly for both incoming and outgoing messages.
3. I have no working experience with the SOS function, but given the above, I would expect it to operate appropriately.
4. It has no voice function
5. It does not receive data beyond SMS so don't expect it to receive GRIB files
6. It did everything it was advertised to do including
delivery of it's preset messages. Take note that these will not
work until the device has been synchronized post any change to the stored data so do this before departure.
If you are looking for GRIB files, you'll need a separate
satellite service like offered with the
Iridium Go and Predict
Wind.
Personally, the SOS function is a "secondary". I'd be seeing the
EPIRB as the primary, a
satellite phone as the secondary and the InReach SOS as a second backup.