(FORTUNE Magazine) – IBM maintains a tight grip as the No. 1 supplier of personal computers for big corporate users, though El Cheapo PC clones keep nipping at IBM's share of the $9-billion-a-year market. Apple Computer's fast and versatile Macintosh hangs in there as a distant No. 2 among corporate PC buyers, with no pesky Mac-clone in sight. Last year a mere one-third of the Macintoshes sold reached businesses. This year the number sold to business users has jumped to 60%. Says David Norman, chief executive of computer retailer Businessland: ''The buyers aren't the people in T-shirts and jeans anymore, but guys in blue suits.'' In the face-off with El Cheapo, Apple's Macintosh has a fast draw: The price of a Mac may be higher than a PC clone, but the Mac is so easy to use that training costs are low. Besides, Apple rewards dealers with good margins, while those on a clone tend to be as paltry as the price. In this confused market, dealers back Mac any chance they get. Impressed by the Macintosh's office inroads, software developers have loosed a flood of new business products for the machine. Ashton-Tate, whose dBASE program is the leading data processing package in the PC market, recently introduced an Apple version of dBASE. Microsoft, which already sells more than half of all software used on the Macintosh, has just released a $295 package aimed at the small-business market. The new package, unveiled by Microsoft Chairman Bill Gates, combines word processing, data management, a spreadsheet, and a program for telecommunications. At Apple headquarters in Cupertino, California, the gloom that has prevailed through a couple of turbulent years is lifting along with profits. They sank last year to $61 million on sales of $1.9 billion. Not only is the Mac perking along, but Apple's $6,000 laser printer is grabbing nearly one of every five dollars spent on printers in the U.S. Says John Zeisler, Apple's manager of business marketing, ''We've suited up, gone into the ring, and started winning.'' Apple Chairman John Sculley takes a cooler view. ''We were lucky,'' he says. ''We couldn't have planned for the predicament IBM is into with the clones.''