Like for a great wine, tasting chocolate uses different senses:

Open your eyes: 
Distinguish the ordinary from the exceptional! The colour does not betray! Perfectly even, shiny, dense and smooth... a great chocolate must be mahogany, never black. Milk chocolate must be ochre, slightly darker brown if rich in cocoa.

Smell it:
It's perfume delicately tickles the nose and stimulates the taste buds

Break it:
It's crack is flawless, it's perfume builds up

Crunch it :
It crackles and breaks.

Crunch it again :
See how it's texture is fine, smooth, greaseless, light ... and how it melts slowly without thickening.

Appreciate it's bouquet and length:
Do you detect the subtle and rich notes of the South American Criollos bean or the more full-bodied of the Caribbean Trinitarios bean that lingers deliciously under the palate...

The subtle combination of bitter and sweetness.

A bitterness without puckery taste and a hardly noticeable acidity, served by  a sweet flavor whose role is to moderate the bitterness.

To discover the subtlety of chocolate, taste it preferably from sweet to bitter.

The quality, in chocolate making, depends mainly on the quality of the used raw material. Where cocoa is concerned, the origin of the beans is of the utmost importance, as for the other ingredients like almonds or nuts, their provenance plays an essential role.

The knowledge of the products increases the pleasure you get out of tasting them.
Therefore is it important to know some definitions:

Chocolate is an intimate mixture of cocoa paste, sugar and for milk chocolate, dairy products in various quantities.

Good chocolate is made of beans of different origins all of which have a high content of cocoa.

The coating

The coating refers to chocolate richer in cocoa butter. It covers the chocolate bonbons with a thin coat. It may be milk chocolate.

The filling

Here is a glossary of the main chocolate bonbon's fillings :

A velvety smooth blend of chocolate and cream. It is often used as the center for bonbons. It can be made from dark, milk or white chocolate or variously flavoured with coffee, tea, cinnamon, spices, alcohol,... it may also contain fruit pulp.

Praliné is traditionally made with ground almonds or hazelnuts.
Not to be confused with the praline which in France means a caramelized sugar coated almond candy invented in the 18th century by the cook of the Duke of Praslin, in Belgium.

Also called hazelnut praliné, a smooth nut paste made of roasted and finely ground hazelnuts and chocolate and sugar, conched together.
Gianduja is also sold without coating: this bonbon is then individually wrapped.

Carmelized sugar with grilled almonds. This mixture is always crunchy.