good quality fish, especially nice yellows will always be popular.
as for the taiwan reefs, personally i don't see the point as they are too similar to the empress & the empress being are more attractive fish IMO. they are kinda the "not quite so hot cousin of the hottie down the road" if you get what i mean. :lol: their only appeal to me is that they are rare but i got over that pretty quick, especially when i looked at my 15cm empress male.
i would have said that the most sought after africans for beginners would something like yellows, fryeri, peacocks then demansoni. Sought after malawis for experienced keepers would not be malawis, more so tangs like tropheus & altos. just how i see it.