If you want color, Malawi mbuna are the way to go. A tank full of yellow Lab's and demasoni is quite a display.Tang's are less colorful in general, though if you look closely they do have a more subtle beauty of their own. Generally though, their main appeal is their unique behavior from adapting to their habitats. Paracyp's spawn on vertical rock faces. The female drops an egg, then catches it (after being fertilized by the male) as it rolls down. The shellies speak for themselves, and the colonial species are unique among cichlids in their cooperative behavior both w/fry and territory. Ultimately it's a question of individual preferences. What do YOU find appealing or interesting? What do you want from the fish?
I know, it's quite frustrating to find that you can't simply pick several fish that you like, toss them together into a tank, and expect them to at least get along, if not thrive. On the other hand, researching the fish before you stock the tank saves their lives, as well as your money and frustration in the long run.
My Tang 55 currently houses a small colony of multi's (may have sold off all the females, haven't seen any fry in months), a breeding pair of buescheri with a few juvies growing out, a half-dozen V. moorii juvies (I'm waiting for a pair to form), and a group of Syndontis lucipinnis/petricola (never did bother trying to positively ID the critters) that still have some growing to do. After spawning and raising SA cichlids I decided to try mbuna, since they don't produce several hundred fry each time they spawn. After finding they were about as difficult to breed/raise as guppies, I decided to try the Tang's for something different. I have another 55 that houses 2 pairs of Hap's and 4m/1f S. fryeri (got 6 juvies, lost 1 female), a group of S. multi's, and a single Julie (Gombe) who holds his own among the much larger Hap's quite well.