I don't really care about product placement as long as it's a... upshot of an action or shot anyway. For example, Em closing the door behind him would usually prompt a close-up on his hand anyway.
So it doesn't bother me that he happens to be wearing a certain brand watch.
It's totally trivial too and if anything, I like it because it adds realism to the 'world'. As, in our world, we're familiar with these products and brands and, anything that can be done to establish a sense of familiarity and resonance with the viewer, I think is a good thing.
The more you believe or buy (

) into the world and whether or not what you're seeing could happen within your world, or within your head - the better.
If it's contrived or forced, then it's annoying. But like, Em leaning up to the glass in "I Need a Doctor"... it seems natural for him to do that anyway, as he's screaming at Dre who's in the tank, in a coma and it intensifies on that moment. So, it's convenient, but justified.
Things like this would normally annoy me but surprisingly, it doesn't.
I see it as an entirely logical and easy way to gain funding. I don't see this kind of product placement as selling out as, I doubt Eminem is doing it for a payday - I'd put a wager on these companies stiffing up the budget for these rather expensive looking videos. So it's just smart business sense, and doesn't compromise hardly anything in my opinion.
And, if Em wears Nike shoes and Nike want to fund the video to make sure he keeps them on for a video or they can get a decent shot on them... he wears them anyway. So it's not really a compromise, just a convenience to be exploited. It's not like he's going out of his way to endorse something he doesn't believe in. As he wears G-Shock anyway right?
So these brands probably become aware of the things he likes then make him offers and do business with him. I'd do it if I was Em, if it meant funding etc. would be silly not to.