Able to use continuously

Heat

Own and use 3 1500W/sec Balcars for more than 10 years and they have never let me down. The unit is fan cooled, but still a bit hot after hours of use. But that seems normal, for I've done shoots of more than 8 hours at a stretch using these Balcars. The attachment of softboxes etc. is done quick and very secure. The built in slave trigger operates by light, and in daylight the units do not "see" each other. But in those circumstances I use radio triggers, works fine. The 1500 W/sec is sometimes a bit much, so it would be better to add another 500 W/sec unit. Operating the unit is very easy, light can be set at 100%, off, or proportionally. The slave trigger can be switched off, as can the beep after flash. It's nice that all units have a slightly different tone of this beep, I can tell exactly which one of the units did or did not trigger. The flash head can be retracted or shifted forward in 4 steps, which adds some fine control with respect to the softness of the light.
I like the simple tilt that you can do with the attachment to the stand.
This Balcar is not cheap, but the light it creates is beautiful.