I was personally unimpressed by the first IBM PC. But please remember I was a Commodore user at the time, and as with the Mac users that followed us, this was a frequent and predictable reaction to outside technology. The PC had expandability, sure, and was made of a tank-like metal that screamed quality as loudly as it screamed cost. It came with reams of documentation, which was also impressive but expensive.
The first PC came with Microsoft's MS-DOS, though IBM called it PC-DOS and historians remember that the guy Microsoft bought this from had basically ripped off CP/M. Speaking of which: Customers of the original PC could optionally choose between two other OSes: CP/M-86 or UCSD p-System.
Once Compaq and other clone makers reverse engineered the PC BIOS, IBM tried to re-take control of its own market by inventing the PS/2 and, with Microsoft, the doomed OS/2 operating system. The PS/2 had some nice bits to it, but its reliance on a proprietary MCA (Micro-Channel Architecture) bus in lieu of the then-standard ISA bus raised costs and started IBM's downward spiral from both influence and market share perspectives.
But its fate was sealed. PCs commoditized, became cheaper and more cheaply made, and are now in danger of being pushed aside by more mobile computing devices. That story has yet to be told.
The IBM PC did, of course, lead to the award-winning line of ThinkPad notebooks, one of the few things IBM did get right in this market. Of course, IBM eventually sold off ThinkPad and the rest of its PC assets to Lenovo when in 2004 it abandoned the market it started.