PCMag.com:

This third-generation TouchSmart PC is boosted by Windows 7’s gesture support, but HP’s custom multitouch software is even more impressive.

But as with the earlier models, on the TouchSmart 600 it’s HP’s custom software that really shines. Version 3.0 is a significant upgrade, offering touch-friendly versions of Hulu, Netflix, Twitter […]

And the HP apps now multitask, letting you hop back and forth by sliding them around with a fingertip. The interface is responsive, and is the benchmark for upcoming Windows 7 all-in-one PCs from Acer, Asus, Dell, Gateway, and MSI.

 Engadget:

[…], but more important is what HP is doing with its own TouchSmart application. It’s added panes for Hulu, Netflix, Twitter and an HP Music Store powered by Rhapsody, which work in nicely with the rest of the touch-friendly apps onboard and a bit of underlying Microsoft technology keeping things humming — like a nice big handwriting pane for quick Rhapsody searches. There’s also a voice controlled recipe app that can capture recipes from popular recipe sites and read them out loud to you, and the photo app can hook up with a phone over Bluetooth and pull off photos.

Gizmodo:

But to really take advantage of the system, you’ll want to use the TouchSmart interface and the wonderful, custom apps.

The one downfall here is that HP has designed TouchSmart to run all of the bundled apps at once. You’re truly multitasking, and that means stacking HDTV, Hulu, Netflix, photo editing, a browser, Twitter, and even more video playback. The system generally handles itself admirably, but the TV tuning definitely tips the scales on occasion (just watch the video for interface stutters). If I were to use the system as my DVR on a regular basis, I’d probably cut down the fat on HP’s apps and buy myself some resources.

I want to love the TouchSmart 600, but I just really, really like it a lot. The functionality is all there; no one can question the full media suite of apps, like Netflix, Hulu, and Twitter, let alone the full Windows 7 OS sitting right behind HP’s optional software. It’s the light performance hiccups coupled with a less than 100% touch interface that stop me from screaming at the top of my lungs, "YOU SHOULD BUY THIS RIGHT NOW OR GIVE UP ON LIFE COMPLETELY."

CNet.com:

While HP has clearly borrowed from Sony in its wall-mounting and video input capabilities, the software designed for its touch interface is unique and just as compelling.

As promising as we find HP’s new touch programs, Recipe Box in particular, we found the touch interface unresponsive at times, and the main touch software carousel can be slow to load.

Neither Sony nor Gateway have put as much effort into their respective touch software as HP has.

You might also appreciate the numerous video tutorials included with the system to help you navigate the new touch software.

Howtohackstuff.com:

HP continues to put its TouchSmart user interface on top of Windows 7 and it is one of the best I have seen. The new stuff comes in the way of applications; there are now loads of new third party applications, including Hulu, Twitter and Netflix. The interface is as smooth as a baby’s bottom and the main set of tiles fan across the screen and you can easily flick to toggle them. Again, check out the full review of the TouchSmart 600 to get a glimpse of how it really works. HP may just have a method to its touch madness.

Laptopmag.com:

Not only is the touch interface on the refreshed tx2 much better than anything else we’ve used on a notebook, HP is adding cool new apps like Twitter and Hulu, with more to come.

What makes the “new” tx2 stand out is what it does with touch.

Unlike the very limited MediaSmart software HP bundled previously, this machine has HP’s full TouchSmart treatment, which means it has the same slick tile interface and nearly all the same applications. These include photos, music, weather, notes, games, a touch-friendly Web browser, and more. Just like on the desktop, you can move smaller menu items to the main menu by dragging the tiles up, or vice versa.

ChipChick.com:

HP has released two new TouchSmart All-in-one PCs and these latest models come preloaded with an  impressive, and very much improved upon set of built-for-touch applications.

GottaBeMobile.com:

HP’s new all-in-one TouchSmart PCs come with an improved touch interface and some new apps. I really like Recipe Box, an application that organizes all of your online recipes. The application can be controlled with your fingers or through a Bluetooth headset. I rarely cook, but I’d probably be willing to spend more time in the kitchen if I had something like this.

The new TouchSmart PCs have a touch interface that’s a lot more lively than previous versions.

The new TouchSmart PCs come with touch applications for Hulu, Netflix and Twitter. Consumers may have fun with these applications, but I found the business applications HP had on display much more compelling.

Edit [adding more stuff just because]:

CrunchGear:

I will hand it to HP and Sony: their interfaces are gorgeous. The HP interface I saw last week has a number of simple tools – a recipe box, for example, that can take recipes from the web and import them into a private database – as well as the standard stretch’n’drag photo and note-taking applications that make touch actually compelling.

I’m sure there will be more, and there will be more criticism too. Developing software is always about trade-offs, and sometimes customers want other trade-offs to be made; that’s why software is never “done”.

But these first few reviews make me feel it was worth the time, working on the TouchSmart software. And yes, the “shell” that hosts all the various applications is still written in WPF. WPF rocks!