A. NO, its awesome!
B. No, it/they're awesome!
C. Ehh, it's a matter of opinion. B/c you asked I assume you'd prefer black? I have a black substrate and love it. Moreover, it does not have to be more expensive. Check out Tuface MVP or Pro's Choice SoilMaster Select, both come in charcoal and you could get 50lbs for around $15, maybe you'd want 100lbs for your tank size.
Do you anticipate you might want to have live plants? If so, those substrates are great for that too. Might want to check out Black Onyx sand, but it's pricey.
D. Heck NO! You've got a great thing going IMO