The more you can standardize the more you can save of individual items. Some other benfits standardizing:
• Users can learn from each other. If one user learns a procedure they can teach it to another. You begin to build an “institutional memory” among the users that transcends the individuals.
• Support is less involved because you spend less time negotiating between incompatible systems.
• You may be able to save by purchasing equipment and supplies in larger quantities than you would otherwise. You can buy software with a site license, often at dramatic savings.
• You can manage and secure the workstations centrally.
• You can substitute an identical or similar computer for one that malfunctions so that the user’s downtime is minimized.
• If everyone is using more or less the same equipment you avoid one-up-manship or primadonnas who insist on this or that configuration.
I’ll admit my prejudices are coming through here. But, pick a platform and stick to it. The benefits of standardization will outweigh any spurious gains and good-feeling that your staff have as they cling to their old familiar machine. Eventually, even the die-hards will get bored with the whole computer thing and realize that they have a real job to do. And if they don’t, then you’ve got a personnel problem, not just a computer problem.