Hardware vendors around the world are finally launching Tablet PC devices based on Microsoft new operating system today, capitalising on the chance to sell a new device into a stagnant PC market. But while many companies are embracing the new Windows XP Tablet PC edition software, others are certain to fail as users determine which devices will pass muster, according to analysts.

"Companies have made many different choices in bringing these products to market, which I think is a healthy sign," said Stephen Baker, director of research at NPD Techworld. "They are showing some innovation, and people think there is an opportunity here."

The two main designs are slate devices with detachable or wireless keyboards, and devices that resemble notebook PCs and whose displays swivel. "Initially, products that offer you multiple capabilities will do best. Exclusive tablets are going to be a much tougher sell, at least in the beginning," Baker said.

Despite the use of various processors from Intel and a few Transmeta Crusoe chips, "I don't think these things are going to be sold on the basis of power," Baker said. The niche businesses that adopt the tablets for their workers, such as health care and large sales organisations, will make their purchasing decisions based on usability more than anything else, he said.

Pen-based computers have historically remained on the sidelines for average computer users, but Microsoft and its partners are hoping that trend ends with the launch of Tablet PC operating system.

"The customers who these products are targeted toward will be willing to pay for the product if they see value," Baker said.

A selected list of devices launched this week follows below:

Toshiba's Portege 3500 Series Tablet PC features a 1.33GHz Pentium III Mobile processor, the fastest chip included in an Intel-based Tablet according to Toshiba. To read PC Advisor's exclusive review click here.

Heat from that increased processor performance will be dissipated through a 2mm space between the keyboard and the 12.1in TFT (thin film transistor) display, which swivels to cover the keyboard when the device is in Tablet mode, Toshiba said.

Toshiba chose a notebook PC-type design for the 1.8kg device. The company has also included integrated Bluetooth and 802.11b wireless communications capabilities in the device.

The Portege 3500 will be available worldwide as of Thursday. It is priced £1,799 (ex VAT).

The Compaq Tablet PC TC1000 (pictured) from HP uses the Crusoe TM5800 processor from Transmeta, which received a clock speed boost to 1GHz for this device. "It's got the right combination of performance and battery life for this highly mobile category," said Ted Clark, vice president of new notebook business at HP. A full review will appear in PC Advisor's February 03 issue.

The display is a little smaller than Toshiba's, at 10.4in, but it is optimised for wide-angle viewing Clark said.

The HP keyboard is detachable from the rest of the device, and is designed to be stored in a carrying case or its docking station when the device is in Tablet mode. Without the keyboard, the TC1000 weighs about 1.35kg with a total weight of just under 4lbs with the keyboard attached. Pricing will be around £1,300.

Other manufacturers entering the Tablet PC space include Fujitsu, Acer, Viewsonic, LG and NEC.

The UK launch is later today, and we will bring you more news as we have it.