Are you talking about the HD Media Link? This little accessory mirrors the screen on the HTC One to your TV. But depending on what you're doing, your experience may vary. If you like to look at photos and basically anything still, then this will work. But any fast paced moving pixels, forget about it. The only game that I've tried that works well is angry birds, but even then it stutters. I don't know how you plan on using it, but I'd say it's not worth $90. ATT gave it away for free during their preorder promotion.
This device, to the best of my knowledge, does not work with any other device besides HTC devices with at least Sense 4.0. If you want your mac/iphone/ipod to work, you need to get an appletv. Hope this helps.