It's not supporting open source community (does not provide OS api for every part of chips) - so either you use their blobs or don't have access to everything hw is able to.
And AFAIK they're heavy GPL violator: https://linux-sunxi.org/GPL_Violations
because on every image on main page (row with three possible use scenarios) it's shown as connected to a display.
This IS freebie marketing.
Not at all. Complete brand-name HDMI connector assembly costs 29 cents in 10K quantity. [1]
[1] http://www.mouser.com/ProductDetail/Amphenol-FCI/10029449-11...
The Raspberry Pi machines use a family of Broadcom chips. These include some kind of general-purpose processor built into the GPU (sometimes called the VC4 or VPU). During operation, it runs an RTOS that handles OpenGL ES calls, translating them to QPU instructions. During boot, it's the first thing brought up; it initializes the RAM, loads the next level bootloader, then starts the ARM CPU. There's an open-source video driver that does the OpenGL work (and I think actually supports OpenGL, not just the ES variant). There's work being done on making a bootloader replacement, but it's in the fairly early stages (https://github.com/christinaa/rpi-open-firmware).
Maybe someone who knows about the CHIP itself will chime in with more detail on how it compares.