My friend Ian was using a Westcott Apollo softbox with his Alien Bees during a recent shoot, and I must say, I like the Westcott Softbox. It is different from other softboxes I've seen in Singapore, and for this one, you don't need a speedring and you can either do it shoot through or bounce off the reflective back of the softbox.
Sad to say, I can't find them in Singapore. Ian ordered his from B&H, and after doing some searching, I like what I see with the Westcott Apollo Speedlight Set.
Julia Greer also wrote a great article on How To Use Your Nikon SB-800 Flash With Softboxes, and in it, she also mentioned the Westcott Apollos.