Re: the touchscreen - I will be very honest - I had no interest in one at all, and you could paint me as one of the fiercest anti-touchscreen crusaders there was. You'll find posts in the dpreview forums from last year stating as much when Sony came out with the TX series cams - I had a beloved T100 with buttons and pads instead of a touch screen, and was very disappointed that Sony was headed that direction with the T-series cameras that I loved. I did not actually plan to buy the TX1 I have now...I was happy with my T100, and would have kept it another year or two for sure. But I had a friend who had bought the TX1, and his girlfriend just had a general dislike of Sony for no real reason (as many people do) - so she wanted him to get something else. Being completely whipped, he obliged, and offered to unload his 2 month old TX1 for $100. Despite having no interest in a new camera, or the touch-screen controlled TX1, I couldn't pass up a $300 camera for $100, so I decided maybe I'd have some fun with the low light features...and just put up with the touch screen.
That's a true story. I still hated it when I first got the camera. Then I started using it. And my mind changed immediately. On an ultracompact camera, the touch screen just made sense, and offered some key control advantages over any other ultracompact camera I've ever seen. First, the touch screen sensitivity has not been any problem on mine - it responds quickly to all presses, even when made through a waterproof bag (TX1 isn't waterproof, so an aquapac is needed) or with a glove. The onscreen buttons are well laid out and easy to press accurately. I'm not sure if some folks get bad screens, or just aren't used to them, or have odd hands...but I can't say I've had any problems.
Here's where the real advantage comes in for me: The touch screen is customizable! You have 4 icons down the left side of the LCD for direct access to controls. By default, these are set up with mostly worthless things for me, like face-detection, smile shutter, steadyshot, and scene modes. At the top, the main Menu button is always fixed on the left. But the 4 icons down the left can all be user-set to whatever Menu controls you use most often. The main menu has all the camera's settings in it - focus mode, focus points, metering mode, metering area, white balance, ISO, scene modes, steadyshot, dynamic range optimization, etc. So as a 'photographer', having access to some of those more used features is nice - on almost all compact cameras, there are no direct buttons for most of those controls, so menu diving is needed, and multiple presses to make changes. With the touch screen, you essentially can render key controls as 'direct access buttons' with one-touch access. My main screen has ISO, focus area, White balance, and EV down the left side. One press of any of these, then an on-screen slider or selection to make the change.
Another very nice touch screen advantage - you have completely and infinitely variable spot focus control by touching anywhere on the screen to focus on that precise point. This is a wonderful little feature that gives a surprising amount of control over what is essentially a fully automatic camera. And when entering specialty modes like HHT, AMB, and HDR, most Sony cameras resort to multi-point focus with no way to override (HX1, HX5, WX1, and WX5, for example). When focusing in low light, it can make it very hard to find focus, whereas spot focus could pinpoint on a particular area and gain focus. The TX-series cameras' touch-focus mode remains active in all modes, so you can touch the screen and grab spot focus anywhere, anytime. Also in the specialty modes like HDR, many users of the HX5 have struggled to properly meter the shot (with HDR mode, the first exposure will always be for highlights and the second for shadow, but since the camera can only use wide area metering, you can't spot meter on a specific area to expose directly for the highlights). Half-pressing the shutter on the HX5 will lock focus AND exposure, so you can't focus in one place, then recompose to meter another. With the TX touch-spot focus, you can - tilt up to meter off of the sky or a light, while pressing spot focus at the very bottom of the screen to focus off of a tree or chair...half-press and you've locked focus and metering in two different spots.
Hope that helps a little. Not that the HX5 has anything wrong with it - it has much more zoom range and GPS and excellent reviews, so it may suit your needs much more than the TX series. But the TX series does have some nice advantages for those who want a little control over the exposures and shots, without having to go to a true manual controlled camera with a larger sensor (and the resultant larger body!). And even some folks like me, who couldn't possibly be more against the touch-screen concept, have been won over by the inherent logic and additional user-control and customization, it affords.
