curryindian-cuisinespices
There are usually two ways of adding khada masala spices(cloves, cardamom etc) to a curry:
What kind of difference in flavor do these two methods create and which is better to use?
If the English curry is similar to this, you are missing CREAM!
Recipe complexity is certainly a factor (as the other answers mention), but there's possibly a bigger reason: masalas often contain a very large number of spices that most western home cooks don't frequently use. While some people (generally more adventurous cooks) are willing to purchase a dozen or two spices and make good use of them, that's a bit much to expect of most home cooks. And if you don't use the spices much, you'd end up spending quite a bit on spices, and not even use them all before they go stale. A lot more people will be willing to make a recipe if they can just buy a jar of premade garam masala and be done with it.
Best Answer
It would depend on the spices that you use.
For fresh spices - whole pieces of cardamon/ cloves/ cinnamon etc., I would add these spices at the beginning with hot oil, so the aroma of these spices would release to the oil. Stewing it slowly would also make the flavor slowly develops.
For adding at the end, maybe you mean adding the garam masala powder. This powder could add back some "kicks" or highlight as some of the "volatile" aromas are lost after cooking.
However, there is not a clear cut between methods 1 and 2, instead, you can add fresh spices at the begining and garam masala powder at the end. Just to make sure that the flavor is kept balanced when you use both methods.