Re: the nightmare of the Beaglebone Black Evaluation of Frustrating Bollocks.
I did what all proper Unix admins do and eschewed this "writing down what I did and why" step of the game for fear someone else would be able to do it without learning how the hard way and anyway I had more pressing things to do than documentation.
It amounted to the following:
Initial purpose-bought 32 gig micro SD card turned out to have *too much* memory for the BBB. I had to comb the area for an 8 gig card (becoming hard to find in my neck of the swamp) before the BBB would do more than do a lego brick impression when booted.
Odd as in "hard-to-find and expensive to acquire a cable for" mini HDMI slot parked so close on the board to another component (don't have the board here ATM but I *think* it was the USB port) that precluded using a simple adapter to step it up to the regular easy-to-find and cheap as chips size for fear the mini HDMI port would be torn from the board (it's a tight squeeze even with a purpose bought cable). Why was this port not shimmed to mitigate this obvious problem? None can say.
Then the bloody thing would not play with an old monitor via a HDMI-to-VGA coupler, though the same hook-up gave the Pi no problems at all apart from an initial blank screen when the firmware is polled instead of the startup console blither, and which doesn't happen on subsequent tries unless you plug the Pi into a bona fide HDMI capable monitor.
Oh, and the external USB Hub took a couple of restarts and a couple of different ones before it was recognized though both were named brands of hub.
That about covers the "Console Mode" boot.
Since sourcing that effing HDMI cable took forever I attempted to access it via the USB interface, from which an administrative webby control port and programming API for the main app (whose name I cannot remember). This is the primary way it is thought the device will be spoken to anyway, and the BBB runs a webby app server to facilitate doing so which on paper looks great.
Problem 1 - the initial "is the app working properly" page with embedded tests showed the page was *not* working properly though the programming workbench app was. I was instructed to download and reburn the OS image, at which point the app test page worked but the programming workbench stopped working.
Problem 2. The SSH app that loads in the browser (same as program workbench etc) would not open a session to the console. This was working fine before I reburned the SD card. I finally solved it by connecting using Putty, but I could not tell you why after that the browser-based thing started working. I made zero configuration changes. The workbench started working too after this. Obviously the problem was in the session, but what, why and how it got fixed? Put me down for a "Splunge" on that one.
At which point the cable arrived in theater but by then I'd lost the adapter I needed to daisy chain the other end to a useful connector (couldn't find a cable that would do everything itself) and after buying another for a mere $25 I was able to connect my HDMI monitor and a keyeboard and mouse to it and get it sizzling using the console.
The cost for all this ran to many times the costs incurred in acquiring the Pi and getting that working. The GUI on the BBB is more responsive than that on the Pi but the overall experience was better for me with the Pi.
That said it should be front and center in everyone's mind that the two machines are very different and intended for different markets. The Pi is primarily a programming workbench in intent, with a tiny but adequate amount of memory available. The BBB is a professional prototyping tool with no fixed mission in life with a large amount of memory on board.
Neither is an economic way of putting together a general use desktop machine given the availability of x86 type hardware and the wide variety of mature(ish) Linux variants that will run on 'em, though the BBB has more carpet for you to spread your digital crap over than the Pi does.
Both could be used in small and specialized devices/applications. The easiest ride and widest support would seem to be for the Pi, though the community has dirty laundry it doesn't like to talk about (as you've seen here).
I don't think either is a particularly good platform for teaching newcomers how to program in an age when struggling against the limitations of a machine for their own sake will be seen as a waste of time, but that is my opinion and not some sort of universal truth.
Good luck with whatever your project is.