My first job required the use of an AS/400 for data entry. Hated it at first, but really grew to appreciate it for what it did. That single machine ran an entire manufacturing site. When we were forced to use a Windows front-end to enter data, it was an order of magnitude slower, it was that cumbersome and inefficient. Other front-ends, doing real-time visualisation of the plant operations were actually useful. But the AS/400 fills an important niche, and it's one which I don't think modern systems do a good job at replacing.