The 105/3 replaced the 104/2, and the 103/4 was the next smaller in the line. It was the first UNI-Q speaker line, and the midrange purity, dynamics, and imaging are as good as anything I've heard. Coloration is very low. Bass is strong, and can overload small rooms, but in medium rooms is very fast and tight. The weakness of the UNI-Q was the top end extension, which rolls off a bit. KEF has used supertweeters and several redesigns to correct that.
Coloration is also very low.
Taking into account plusses and minuses is always a personal matter, but I'd rate them about as good overall as a speaker like the Joseph 22si Mk2, and better than any $1k speaker I've run across overall. I've ot heard the 104/2, but it has an excellent reputation.