I'd recommend the
non-T Cyo Premium, which (IMO) hits the price/light quality sweet spot for those lights currently available. (model number 1752+letters)
The non-premium Cyo (aka Cyo 60) is a little less bright, but the main drawback is that the beam is a fair bit narrower (model number 175+letters).
I don't like the daylight running lights (="T") models. The daylight LEDs (the 4 slung under gregoryoftours' light) use as much power as the main beam LED, and I don't want 7 or so watts of dynamo drag all of the time, rather than just when I'm getting some useful light out of it. You can turn the light off, but then the Senso function won't work, and I find that useful enough that my dynamo lights spend all of the time in Senso mode.
The IQ-X and IQ-XS don't have a non-daylight running lights option, and there's the somewhat dodgy soft switch mentioned by PH. I dare say it's OK if you have the light turned on 100% of the time or never leave the bike unused for long enough for the standlight capacitor to discharge, but I have heard tell of people not being able to turn the light on until they are riding, or have ridden far enough to put some charge in the capacitor if the switch isn't reachable from the saddle.
I notice that the Cyo has dropped off the B+M website, so I expect it won't be available for too much longer. So has the Luxos U (with USB output, and a poor reputation for reliability).
In other news...
B+M are meant to be introducing a
new IQ-XL light "soon " that's properly bright, almost like a car - 300 lux low beam, 250 lux high beam, with a handlebar switch to toggle between them. €300, and with daylight running lights though
SON are also introducing a new light (
Edelux USB-FL) with a similar high/low beam switch. It apparently won't be all that much brighter than the B+M IQ-X, but the gimmick is USB power up to 7.5 watts via a handlebar switch socket, even with the lights running. Just the thing for those who navigate by smartphone?