HI there, how interesting that this very very old and forgotten thread of mine (it seems to have come from a different life!) has resurfaced. I do have an update from the situation as it was 8 years ago! Here it is, if anyone is interested:
My DS remained non-speaking (I prefer that term these days to "non-verbal", as he is very verbal, just not with speech) and in the end we did not go with the Lightwriter, as he learned to type, first on a laptop, then on a tablet, then a mini-tablet and finally on a phone. He is now 13 and just wears a phone on a lanyard around his neck, with text-to-speech software and a voice synthetiser on it, so he can "talk" (you can hear the voice, and he can also show you what he has typed, which can be handy, especially as new people sometimes don't clock on immediately that he is talking to them). It is very non-stigmatising as everyone has a phone, so looks totally "normal" and just like any other kid who is constantly glued to their smartphone! It is also cheap and easy to replace, as opposed to specialist devices, and so no need for insurance or excessive worry about it breaking (he's a teenager, it does get broken!). He "talks" constantly and has a good level of language for his age. (He is now responsible enough to take charge of making sure it is charged and that he always has a spare when he goes out).
The thread was however resurrected by someone asking about an adult who had a stroke, and that would be a very different situation, especially if there are motor control issues which could affect typing ability. I have to say that I have found over the years that many SLTs know little about the specialised field of AAC, and it is vitally important to do your own research and not wait for or rely on advice. The tech has moved on a lot since the days we were looking into a Lightwriter and the software available on tablets, laptops and phones is much more sophisticated and diverse now, at a fraction of the price. Having said that, of course many people do need specialised devices (including for example eye gaze tech, or spelling tech), I would really recommend getting onto AAC groups on Facebook and elsewhere if you can, to see what different people are using. (I belong to an AAC Users in Ireland group on FB, for example and they have a lot of interesting information. There are many more people using AAC than you realise, especially in the States, and it is worth getting in touch with people, there is now such a variety of devices and apps out there).