The Roku 3 is the flagship Roku streamer, but not the latest. Last fall Roku re-released the Roku series in a variety of configurations.
The Roku 3 is distinguished from the rest by 1) its lack of composite out, and 2) its 5x faster cpu. The Roku 3 and the latest Roku 2 both have an earbud jack on the remote and the requisite wi-fi remote.
The 5x processor has no impact on streaming media performance. Obviously, it excites people who navigate the menus a lot, but some who have owned the R3 for a while complain that the interface gets laggy after a couple days and that the Roku needs to be rebooted to restore satisfactory performance. In theory, the faster processor should help with apps (games), but, to date, no app has been released that taxes the slower Roku models.
Two issues with the remote: 1) Running the wifi radio to stream audio to the earbud jack dramatically reduces battery life, and 2) some have complained that the Roku has adversely impacted the response of the remote and other wifi devices on their network. Unless all you listen to privately, you may be better off getting a wireless head set that plugs directly into the television.
Lack of composite output means you cannot use the Roku 3 with a television that does not have an HDMI input. Make sure your television has an HDMI input before pulling the trigger here.
I use the composite out for audio in on my sound bar and HTIB. The roku in my living room is attached to a 50" plasma. My wife uses the Roku as an internet radio. Rather than leave the 50" plasma running all day, I routed the composite audio to the aux in of the HTIB and turn off the tv once the radio is running -- less wear and tear on the television and a lower electricity bill.
I'm not saying you should not purchase this Roku 3. The price is right. Just wanted to point out some stuff that is not printed on the box ;-)