I have used this for a few months now with no issues at all.
The "bulb" is a hemisphere pointing down giving about 180° vertical and 360° horizontal exposure.
The light itself is as described a blue white and is excellent for the bathroom, office or kitchen. It is definitely has a true white or blue shade compared to the original filament bulb but seems nicer than some of the CFL (compact Florescent light) light bulbs. Note the box states 4000K colour temperature (see wiki). This colour makes the white paper for my printer look very "white" (like recently washed white clothes on a bright day - unlike others that give a yellow/red hint).
The 5.5W states is equivalent to a 30W filament bulb (~290 Lumens). I would that's probably about right, maybe 25W. It illuminates a "standard" single bedroom, en-suite bathroom or small office perfectly. However, I would personally go for a 7 to 9W version next time.
It is instant on and the bulb never gets warm. However, the "heatsink" above the unit (where the mains cable attaches, using a barnet style connector "B22") does get warm after 1 hour or so. But still much less than a 30W filament bulb.
If you have a small bedroom/office/bathroom this is a really good choice to save energy.
Overall rated 4 stars as its a little expensive and it is not dimmable, but probably worth it for the long time energy savings.
I would also recommend going for the "warm" type where the colour is much similar to filament bulbs if that is your preference, e.g. for a warmer feeling bedroom. But I would definitely go for higher power.
Lastly, I cannot comment on longevity but this bulb is rated highly on the box (24,000 hours, a little less than some other competitor LED bulbs).