Teams should be allowed to use whatever tools best suit their work style. We stopped the draconian IT practices a year ago and now allow our developers to have literally whatever they want for a laptop. Productivity went up. 2/3's of the team runs Mac, 1/4 runs PC, and the remaining fraction run Linux. Seems Mac is the clear winner in my shop. Interoperability issues are somewhat a part of life, but the good outweighs the bad.