Late last year, Google gave laptop prototypes to a few thousand chosen customers. Google was soliciting feedback for the Chromebook, a \"cloud,\" or Internet-based, machine meant to buck the status quo of personal computing long propagated by Microsoft and Apple. The Chromebook\'s underpinning is Google\'s Chrome operating system software that resembles and behaves a lot like the Chrome Web browser. The pitch: Your apps, documents, settings and other data will be securely stored in cyberspace and accessible from any Chrome computer. Google warned testers at the time that the pilot notebook was \"not for the faint of heart.\" So true. The first Chromebook models, from Acer and Samsung, went on sale Wednesday at Amazon.com and BestBuy.com. Acer\'s Chromia-branded Chromebook models include a Wi-Fi-only version for $379.99 and a Wi-Fi-plus-3G version for $449.99. Samsung\'s versions are the Series 5 Wi-Fi model for $429.99 and the $499.99 Series 5 with 3G — the model I\'ve put through the paces. Chromebooks raise an important question: Are folks ready for a cloud computer largely crippled when there\'s a shaky online connection or none at all? My suspicion is that will be a tough sell, especially for non-techies. Google isn\'t the only tech titan hoping to reign supreme in the cloud, of course. The search giant can expect spirited competition from Apple, among others. Last week, Apple provided the first glimpse of the iCloud service it plans to fully launch in the fall. Apple\'s OS X Lion operating system, coming this summer, also is expected to deliver features that overlap with Chrome OS. The new Chromebook is a breeze to set up. Enter your Google account name and password, and your Gmail, calendar appointments and settings are synchronized. The machine starts up in less than 10 seconds. It wakes from sleep in an instant, and also has impressive battery life. Google claims about 8½ hours of continuous use. My test unit still had juice into a second business day of normal use. The Samsung\'s plastic white cover brings to mind an Apple MacBook. The Chromebook weighs about 3.3 pounds and sports an easy-to-type-on keyboard with refreshing modifications. The rarely missed cap locks key (which you can bring back in settings) is replaced with a search/new tab key. Gone, too, are the function, or F, keys at the top of many keyboards. Instead, you find keys that are useful in a browser-based environment: back, forward, reload, full screen and next tab. I\'m lukewarm about the finger-gesture-driven touch-pad. There\'s an SD memory card slot, two USB ports and a port for connecting the Chromebook (via adapter) to another display. The Chromebook has a decent 12.1-inch display, modest \"local\" storage and a webcam that you can use for Google Talk but not Skype video chats. Chrome OS software is based around the notion that we spend an awful lot of time prowling the Web, reading e-mail and engaging in apps that reside on remote servers. I wrote this column on the Chromebook using Google Docs. You can fetch and easily install free and fee-based apps in the Chrome Web Store — there are about 4,400 available. If you lose the computer, you can restore data from the cloud on another machine. Chrome software can be automatically updated with new features or security enhancements, eliminating the need, Google says, for anti-virus software. But there are drawbacks. Many Web apps that run in the browser are not as full featured as traditional software. Google Docs lacks many tools found in Microsoft Word, for example. You can\'t connect a USB cable to print. Printing requires an ePrint-capable wireless printer or you have to go through the Google Cloud Print service, which means having a separate Windows PC connected to a standard printer. And while Google and its partners have devised \"hundreds\" of Chrome apps that work offline, including Angry Birds and an app that caches the Wikipedia encyclopedia, you want more. Google says offline versions of Gmail, Google Docs and Google Calendar are expected this summer. Models with 3G wireless to complement Wi-Fi include 100 megabytes of free data from Verizon Wireless for two years, a small sum. You provide your credit card but will be charged only if you exceed your allotment. You can pay $9.99 for a 3G day pass or choose a monthly plan that starts at $20. I was able to watch videos, play music and upload pictures stored on an SD card to Picasa. I also streamed music via the cloud Google Music service that is still in beta. Netflix streaming is not yet available.