I honestly keep a list of everyone i've bought coral from sorted as best, good, meh, haven't tried and avoid... with my thoughts as well as what good/bad things i've heard - for BC you're in the Best Category and in my notes i have "Great Customer Service" as just one of the good things...
Good Service to me makes me feel like i'm your most important customer at the moment... or that you're taking the time and effort to go out of your way for me... it's basically value added to the money transaction that has or will occur... my favorite places in the hobby do this and i keep coming back cause i'm really getting my money's worth... even if it's the small things like an unsolicited DM on a forum with some advice

.
Also honesty and as much transparent info as possible - coral is tricky with colors in different lighting par/spectrum and parameters and colony vs frag... i think most of us understand the frag won't look like a colony - but when we buy something it's because we like what we see... if i want to replicate that it's nice to know how it was raised... ask 3 different people what medium light is and you'll get at least 3 different answers... tell someone it's kept in 250-300 par and it's a fast grower in your system - that i can work with... if i ask about a frag (hey do you have any of this available) - "not now but possibly in 4 months" or "not in foreseeable future cause colony isn't doing well/ slower grower, or lost the colony" is a better answer than just no or not now...
if i know i'm ordering a 1/2" - 3/4" frag that's not wysiwyg it better be at least that... some of the camera angles on wysiwyg are deceptive also hiding issues, pests, blemishes, or making things bigger than they seem etc... Worked out a deal with a vendor for a few additional frags once and thought i was getting a good deal on a package but ended up just getting the smallest frags possible (healthy though)...first time i ordered from them and won't be doing it again anytime soon - they're in the meh category, basically ok to buy from but little to no added value... if you consistantly give me more value for my money i'll consistantly be back....
#1 thing that annoys me though is being given the run around/ non answer or ignored... i get it a lot with inattentive companies who don't seem to have their act together.
example: had overnight fedex package get delayed friday at the local hub (got notification on tracking for delay and that would be delivered on monday) and wanted to pick it up... first call to CS guy calls hub they tell him they held the truck already and i'd have by noon... he relays this to me and fantastic... afternoon nothing changed with tracking i called again and CS just read me everything i already knew on tracking... they didn't check with hub to see if still there or anything.. i asked if i coudl pick it up and they said yes... so i went to hub. i did get it but also foudn out they were planning to deliver later in day... which could have saved me a trip. I didn't mind picking it up at all... but it really just seemed like they didn't have their act together at all... i've also had to call them in past about their drivers just leaving packages in mud and rain without a bag covering it or anything... multiple times i was told "we'll address it"... they never did and i was calling a couple times a week with number of packages i was getting...
Also for non-answers in daily life - If i ask multiple questions in an e-mail i expect mulitple answers or at least acknowledgement of "I don't know" or whatever in response... i hate having to follow up when only 1 of my 2 or 3 questions gets answered and the others ignored... i get people are busy but that's why i try to include all my questions in the e-mail so that we don't have to go back and forth multiple times... just take the time to read and understand my question... if i repeat or ask in a slightly different way you're not hearing what i'm saying... after 2 or 3 times of that i give up....
I guess to sum it up... communication and value is key... I think BC does both those pretty well...