I received my Speedlite flasgun today, so I haven't tested it all the way. But for what I have tested in an indoor situation, where the internal flash causes a problem (taking a photo of my guitar on the wall, where the internal flash causes reflection on the body and also an 'ugly' shade) the picture now looks superb!
Also the brightness (fully adjustable), the way TTL works and the speed of this flashgun, keeping up with the burst shots of the camera, promises to guarantee a whole lot of photographing pleasure!