[asr]

I'm pretty sure the latest version of worksite/workshare (never was sure which is which or what all the names are) can diff PPT files; apologies if I'm misremembering but that is my recollection from my firm.

I agree the developer needs to take a look at these if he/she has not already but there's plenty of room to improve on those products; I don't think the existence of some mediocre solutions should put the developer off.