Many new second- and third-generation models are emerging, and Dell inc. is planning a convertible model in midyear, Shim said. Dell would not comment, but Shim said Dell's entry could dramatically improve sales of tablet PCs, if only because Dell has a reputation for its ability to flood the market with less expensive devices.

Dell's entry will also come about the time that miniature tablet PCs hit the market, including the 1-lb. OQO with a 5-in. touch screen. But both Shim and Fiering said ultramobile PCs, including tablet PC variants, will stay in their infancy for the next two years, partly because of high cost and relatively short battery life.

Hewlett-Packard Co., Lenovo Group Ltd., Gateway Inc., Toshiba and several other vendors offer tablet PCs, but "none are clear leaders and all are kind of running in last place," Shim said.

6. Tablet PC software for pen-enabled and touch applications has not been widespread, nor has it always been effective, until recently.

"The good news is that support for most key vertical industries and from major ERP vendors now supports tablet PC clients," Fiering said. Recently, more form application-creation tools have appeared. However, some typical PC applications, such as Adobe Systems Inc.'s Photoshop, don't fully integrate pen input, she noted.