I thought the Tungsten was a bit bigger than the TH55 but in actuality there is not much in it, the Sony is slightly heavier but that extra weight manifests itself in a a more solid feeling and higher quality device, dang, if only the TH55 had a slide out keyboard it would be even more superb than it is. I think you can see from the photo that the Sony screen is much crisper, the icons are sharper and clearer and there is a bit of blockiness about the Tungsten W ones up close. The W screen just appears a bit washed out. Could be down of course to a bit of wear and tear about the TW screen as it is a couple of years older.
The TH55 also wins handsomely on speed, applications open very quickly and it is devices like this that give the Palm o/s it's reputation for speediness and minimal lag. It is devices like the Tungsten W that don't, what possessed Palm (apart from cost measures) to stick in such an underpowered processor? The Tungsten C is far better to use in comparison and feels quite modern in useage.
Isn't it odd to see one of those sticky out antennas again? It does have the distinct advantage though of getting you a better signal, I personally don't think modern phones get such good reception without them. I can't recall having reception problems with phones until they started dumping the external antenna.
I actually find it quite annoying, if I could the best of the three devices I'd have a great PDA. Take the phone capability of the W, add in the size, solidity and screen of the TH55 and then the icing on the cake would be the C's keyboard and speed. Sadly it didn't happen and nor will it ever happen.