The keyboard was horrible, yes, but that was fixed within months (I think people could swap the keyboards for free?).
But for the money you got a lot more than the other home computers: a floppy drive, a computer that had a real
operating system, 128K of RAM!, compatibility with most PC applications, etc. Plus this was the computer that made
the Sierra Adventure games shine! (the enhanced graphics and sound made Leisure suit larry a lot better looking than its PC counterpart).
The BIOS interrupt changes may have caused some problems (the keyboard was mapped to the NMI, so you couldn't
touch it while transfering files f.i.) or compatibility issues, but that was only of minor concern at the time.
I still don't consider the PCjr a poorly engineered machine. There were better contenders in that category (some of the Franklin PCs, for instance)