So, first of all, the game: Saints Row 3 is an awesome game and if you have any interest in open-world shooters then you ought to buy it.
But is it worth shelling out for the Platinum Pack? Well, you do get the Professor Genki pre-order content with this pack, which is good if your only other choice is a standard edition without it. But the headphones are, sadly, rather meh - and their description is an outright lie. They do not make you sound like Zimos. Zimos's voice is bandpass filtered and autotuned, T-Pain style. The voice effect on these headphones is a very generic echo which sounds nothing like it. The sad thing is, you COULD make headphones which autotune, but I guess it would be a bit pricey for a video game bundle. Oh, and it's a bit daft they don't work with Live, although they may work if you have any add-on that gives the headset output on the controller a standard jack.