Hi Richard,
I’m surprised you feel the 4700 and the 310 are similar in direct sun.
I find the 310 so much better.
I rigged up a jig using a Littlemore Scientific architectural light
meter (reads out in LUX) that I could use to measure light output. I
get 60 or 70 LUX from an IPAQ 3970 and 270 to 300 LUX from the 310. I
also have Garmin NUVI 260 GPS and I get the same 270 to 300 reading
from that, the rumor is that TomTom units are a little less bright but
I don't have one to test. The point is that most GPS units you run
across are probably about as bright and as direct sunlight readable as
the 310, so all you have to do is borrow one from a friend and you can
do the PDA/GPS comparison yourself. The 310 isn’t perfect, just lots
better.

I don’t think the 310 can be made to run in Portrait but there will be
other, similar devices that will. For instance, the MIO C520. And a
lot more coming, these are just the first in a wave of new gadgets.

Don’t forget Serial to Bluetooth adapters which seem to be working as
input to the 310. Output may be another story.

You are right about cost effective, $180 is very effective. With the
money you save you can buy the more expensive ZAON XRX and a bluetooth
adapter and, if as I suspect SeeYou someday has the feature, you could
display inbound threats on the screen in their relative location.
Already this is working with FLARM.

As far as the Ultimate and the Clearnav, these are not options for me.
I simply CAN’T mount them in my glider, don’t have the room. I did try
to buy an early Clearnav with the idea of rigging some kind of mount
that would allow it to be swung up and lay flat on top of the glare
shield. The ClearNav and Ultimate screen are just too big for my plane
and also too big for my needs, I really want very little from a flight
computer other than my arrival altitude at various landing points and
the bearing/distance to those places. If I decide I want more
information from a larger screen, one option would be to mount two HP
310’s (I think of that option as a "Ramm Mount"). If I had a Stemme
and a huge panel I would put in an Ultimate in it running SeeYou, no
question.

Thanks for your discussion and opinions