I have a Seca 400. The beam pattern is superb, nice and clean with a good spread.
However, the mountings are awful. The rubber band is just not secure enough to hold it steady in bumpy terrain, especially on 25.4mm bars. The helmet mount is utter cack too, it ends up with the lamp stuck far too high up, and the ‘bar’ to wrap the rubber band around is too narrow diameter to get a firm mount. Add in any rain and it continually ends up slipping down. My old Solo had much better mounts, on the bars and on the helmet.
In my case it was underpowered – I used to ride with people with low-power lights so it was fine. Now I play with the big boys and it was getting drowned, so I bought something else.