I've been using a Seconic L308B since forever, at least back to sometime in the 1990s and like all good meters it still works. It is simple and is virtually foolproof. The current L308S is a fairly simple upgrade to match more closely with the needs of digital photography and should be just as good.
It lacks some refinements like a rotating head for the sensor, but for all normal users this is not a problem as being primarily an incident/flash meter you will be operating it with the sensor on the same side as the display anyway. Its only inconvenient if you are using it for reflected readings, but this is not its primary function and most folks will be using their cameras ttl metering anyway for this.
You can download the manual
http://www.sekonic.com/downloads/l-308s_english.pdf - Seconic produces a whole range of meters, but this is the most sensible for most users. It really pays to read the manual. Lots of people have reviewed it on Amazon and give a good impression of both how well it works and some of the things you may get wrong.
The only real consideration is that the indicated ISO on a digital camera is far more of an approximation on
some digital cameras than it was in the days of film. Equally unfortunate is the fact that doubling the ISO on some cameras does not always double the sensitivity, especially at the higher ISOs. For ttl metering the manufacturer is able to compensate so it only becomes a problem when using a seperate meter. The meter itself is very accurate however.
This is not the problem it might seem since the majority of photographers tend to stick to common set ups and it is easy enough to calibrate the meter against your particular camera
if needed.
One particularly good feature is that the L308 uses 1 AA battery that lasts for ages. Some meters use less easily available batteries which can be a bit of a pain.
I use it a lot less than I used too as for frontal or diffused lighting ttl flash metering with bracketing is adequate for many situations, however for multiple light set ups where you are interested in balancing the lighting it can be essential when you are rigging the lighting units.
One further use is that I use it for getting good estimates for inaccessible subjects like birds in flight - just remember to point it at the same angle towards the camera lens as it would be if it was attached to the subject. As the light in this case is being reflected from the ground on both the subject and the meter the difference in distance will usually have negligible effect (exposing for the moons surface needs much the same 'daytime' exposure whether you are shooting from the earth or are actually there) , and the lumosphere is compensating for a whole range of variables it can be more reliable than some ttl metering systems with poor spot capability. The same problem with camera ISO accuracy does apply here as well.