Need some advice on how convince my event organiser not to get a Mac

Hey guys in a bit of a jam, I run the media desk for a local youth music scene thing, and we are due for a new computer. The overall organiser has got into a bit of a Mac craze lately (new iphone, 2 new iPad's 3 new Macs, all for home use though) and while I have nothing personally against Macs I have found things have a habit on going wrong at our events and we have a mac I doubt I will be able to quickly handle it. Aside from this we use the computer for many purposes (presenting video/images, recording basic sound and even power point sometimes, plus we often display words of songs or whatever). Basically as I have only used Macs at uni I don't really know the ins and outs of them beyond basic usage. So aside from the price argument how else can I convince him not to get a Mac and to rather custom build a media pc or something

TL;DR: Please give me some advice on how to convince an event organiser not to purchase a Mac.

(I'm not trying to start a mac vs. pc argument here, it’s just as I have being using pcs for so long I can handle running an event on them however not a mac)