The delay is a few tenths of a second and probably the least of all disturbing, especially since the full luminosity is present equal. A real advance over fluorescent energy-saving lamps! Shortly after turning off the lamp is lit again for a moment.
A flicker is absolutely imperceptible.
The luminous intensity I find very high, more like a 100W bulb, over the previous 20W fluorescent lamp, which was old, however, even strikingly bright. The light color is very good, indeed "hot", but with good color rendering. There are cheap lamps that illuminate only just yellow.
The heating of the ceramic body and the glass is slightly above the pain threshold, ie above 60 ° C, but leaving no lasting damage. A few kids tears after touching can not be excluded.
In case of premature failure I'll post it here as well as for any warranty processing ...