Plastic Logic on Thursday unveiled its long-awaited Que electronic reader, announcing that the competitor to Amazon’s Kindle DX will be available in mid-April.

Geared toward business professionals, the Que has a 10.7-inch diagonal display, one inch larger than the Kindle DX, and can display documents in Adobe PDF and Microsoft Office formats. The DX can’t do the latter, but Plastic Logic is charging considerably more for its device.

The Que will cost $649 for 4 GB of storage and support for Wi-Fi only. For $799, a buyer will also get access to AT&T’s 3G broadband network to download books, magazines, and newspapers from the online Que Store. Amazon sells the Kindle DX for $489, including 4 GB of storage and a 3G connection to buy content from the online retailer. There’s no Wi-Fi support.

Plastic Logic debuted the product at the International Consumer Electronics Show in Las Vegas. The company has been talking to the media about the Que for months.

Plastic Logic is hoping professionals will be willing to pay the higher price to get a device that can access most of their documents while on the road. The larger screen will make it easier to read diagrams and other business-related graphics, as well as text. To emphasize its focus with the Que, Plastic Logic is calling the device a “proReader,” rather than an e-reader.

“The Que proReader was built from the ground up for people who need to read,” Richard Archuleta, chief executive of Plastic Logic, said in a statement. “Starting today, mobile professionals can look forward to a paperless briefcase, a lighter load, and a better way to work.”