mmaarten:
Taking a satphone isn't that bad. It's just one of those devices which can help you to "live your dream".
I totally agree, you cannot expect to simply dial 911 and instantly your worries are gone. You cannot repair a flat tyre with it and it doesn't supply you with water or spareparts, but along with good planning and preparation it can help you surviving a hazardious situation. BTW you also cannot expect to drive off into the desert, get a flat tyre and be rescued by a movie-crew (yes , you were lucky).
See it as just one of those modern wonders; a device like a gps is much more convienient than a compas although you could skip both and navigate on the sun and the stars, you can make fire by rubbing wood but I prefer a lighter.
If you do take a satphone collect some contacts (the campsite you left yesterday, the local HUBBmember who offered you a 2 days further on the road) and be preparred to wait a few days untill help arrive.

One aspect of a satphone almost never mentioned is the possibility that the people backhome can contact you when there is an emergency situation on their side of the globe. Although I can imagine you just want to escape from all this backhome, for them it's quite reassuring (and easier to coop with your travels) if they can send you a sms the moment they desporate want to get in touch with you.

About epirb
I looked into those 2 years ago and decided to go for a thuraya satphone.
An EPIRB is a maritiem device, since a short while you can find them for land use too called PLB. Those are registrated devices, the name, lenght and type of vessel are signed to a code this beacon will send in case of an emergency. These devices are not very cheap and because of the registration difficult to find secondhand, if you can find one you have to make a new registration otherwise the beacon will send a wrong i.d., an oiltanker in the middle of the sahara or a yaght in a rainforrest ?
And one of the main reasons to choose a satphone, you have to get your license (in the netherlands called Marcom-A) to own and or registrar a EPIRB.
A EPIRB beacon will send your coordinates to a rescue party, a thuraya can double as a gps (altough very basic) and can send your coordinates via sms to whoever you want and offcourse you can speak to them.

regards

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bart & sophie