Ho hum.....one more Mac user taking an opportunity to complain about how hard it is to install Linux. Gee that's new!
Maybe I'll write an article about how I tried and tried repeatedly to install OS9 on an old UMAX S900 and guess what? OS9 didn't have drivers for the SCSI controller BUT Debian GNU Linux did.
Maybe I'll also write about the local Apple retailer explaining to me that an old Mac needs to run OSX or it won't even be able to get on the internet but neither of those issues (like your md5sum problem) has anything to do with installing an OS. You could just as well have written "Linux sucks because I don't know how to download a large file." How did you download the .iso? You should never use a web browser for such a thing.
You say:
" in the end that plethora of data turned out to be the biggest problem of all "
Well it used to be "hey there's no documentation for Linux" now there's too much?
How can there possibly be a perfect list telling you which distro a noob should install? Too many variables make this a nearly impossible task.
What hardware are you installing to?
Dial-up or broadband?
Server, workstation or desktop?
Personal needs/preferences.
Why do you want to install Linux anyway?
A: You have nothing better to do.
B: You want to learn something new.
If your answer is A then you probably have the wrong motivation, if it's B then I'd say you're off to a good start. ;) Linux isn't Mac and Mac isn't Linux so you just can't expect them to be the same.
Let's also remember that Linux is free (no I'm not referring to a dollar amount). Macos is not free in any sense of the word. Nothing leaves Apple unless it has been blessed by the hand of Steve but there is no equivalent for Linux (thankfully) That fact alone (well that and the expensive proprietary Apple hardware) is more than enough to cause this average joe to to steer entirely clear of all things Apple.
A Mac User Tries Linux Part 1