As for the touch functionality of the screen, it works exactly as advertised: In addition to using the computer normally, you can reach up and tap, scroll, or even zoom on any page (pinch-to-zoom support still isn't enabled by default in Chrome OS, oddly enough, but all it takes is flipping a switch in the chrome://flags section to get it up and running).
The C720P's touch panel is accurate and responsive and quite enjoyable to use. You could ask whether you really need touch input on a laptop right now — a fair question, and one only you can truly answer.
For a bit of personal perspective, I use the Chromebook Pixel almost every day and have really grown to appreciate having the touch functionality in place. I wouldn't say it's something I need, but it's a nice addition I enjoy having.
As I wrote when revisiting the Pixel last fall:
With the amount of time we spend using smartphones and tablets these days, being able to reach out and touch a screen feels quite natural (how many times have you seen someone inadvertently try to scroll or pinch a display on a standard laptop?).
I don't use the ... touchscreen every minute of every day, but it's nice to be able to reach up and tap something, scroll down a page, or pinch in to zoom when I feel the urge.
Whether or not it's right for you, one thing's for sure: The fact that the C720P offers touch input at an entry-level price is pretty significant in the grand scheme of Chrome OS's evolution.
3. The performance (and other internal differences)
You knew there had to be a catch, right? Here it is: The C720P Chromebook has only 2GB of RAM — half the amount present in the base C720 model.
In using the C720P, I can definitely detect the difference — but even so, I've been pleasantly surprised at the level of performance the system provides. It's less snappy than the base model but still quite usable and responsive; thanks to its Haswell-based processor, it doesn't suffer from the same low performance ceiling we tend to see with ARM-based Chromebook devices.
The system does, however, has its limits. While the base C720 model never feels sluggish, even with as many as 20 tabs open, the C720P starts to get noticeably slower once you hit around a dozen or so open tabs. I've got 18 tabs open as I'm writing this now (yes, I'm working on the C720P as we speak), and the system feels like it's struggling a bit to keep up. I can still get around without a ridiculous amount of delay, but switching tabs sometimes takes a couple seconds longer than it should and trying to open a new app or tab is far from instantaneous. I'd describe it as more annoying than detrimental.
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