IMO the ultimate is the best all round, day to day brush of them all. It eats through spiders nests etc and covers more surface area than the Xtreme- which results in more efficient cleaning for a very minimal trade off in weight. Xtremes, I find, are good for extreme situations but for normal day to day stuff just don't cut it quite enough. Get a spiders nest in the corner of a lower sash window and you can be there for ages trying to hook it out- if you can get it out at all. The medium Ultimate whips them out for fun. I also believe that the Ultimate could still shave some weight off even further too... if Alex put his mind to it.👍 As much as I might wish the Xtreme to be as effective as the Ultimate, the reality is, it just isn't. The flocked and softer ones aren't stable either IMO, the stiff sill version with the lowest (red) bristle row removed is quite good but the extended stock ends prevent the bristles getting into the corners- especially on lower sash windows.