There are many types of chocolate out there, some higher quality than others. What are the main differences between good quality chocolate and cheap chocolate? And in practical applications in baking and confections, what "benefits" do higher quality chocolate offer?
Good quality chocolate has a number of distinguishing features:
Poor quality chocolate will have a low cocoa solids percentage and vegetable oil instead of cocoa butter.
In baking milk chocolate and othe low cocoa solid chocolates are not appropriate as they have a weak chocolate flavor which dissipates during baking do a finer chocolate is necessary.
Milk chocolate may go rancid and taste of 'bad olive oil' as note here due to the fats in the milk going rancid.
In this image the cocoa solids go up from 0% in white chocolate to a maximum of 100% in the highest of quality chocolates. In white chocolate look for no vegetable oils and vanilla extract.
I'd really suggest you read the wikipedia on chocolate processing as a starting point. http://en.wikipedia.org/wiki/Chocolate#Processing
There are many steps involved, and each one is important.
A summary of things that can go wrong:
5 and 6 go more to texture. You may find mass market Easter chocolate has a grainy texture -- That's poor conching.
Then the recipe has to be taken into account as well. Cocoa butter has value outside of chocolate making, and it may be replaced with cheaper oils (Hydrogenated coconut or palm oils for example.)
The cocoa solids themselves may be adulterated with cheaper ingredients to stretch the yield. And the mass producer's favorite weapon is more sugar. If you make it sweet enough, a lot of people won't notice the low quality product.
I'd recommend that you go out and buy a Lindt 70% cocoa bar and give it a taste. While not necessarily the best chocolate out there, it is readily available, and of a decent quality.