It's really a good thing!
How does it regulate the market?
Well the basic rule of supply and demand dominates the market. This means that there can be multiple people selling the same product but each could be different. They could be cheaper to draw the business from the other bussinesses. This would drive the others to lower their prices as well. This also means that there is more options of the product, different variations that may be better suited to certain people.
Apple or Android?
This is a major question that many face when it comes time for a phone upgrade. Samsung Galaxy S5 is water resistant but plastic While the Iphone 6 is thinner and is aluminum. I phone is smooth and seamless but Samsung has a way better camera which is the defining perk that many go for. Personally I went for the Samsung S5 active because it can go through a lot and still work just fine but an Iphone is much more attractive.
Mac VS PC!
Now this is a common dispute between many people! Microsoft focuses of the software part while Apple does both hardware and software. This means that Apple can optimize and protect its computers better than Microsoft. The downside to Apple is that there is only one product to choose from which leads to high prices.
Nike VS Adidas
Nike is known for its Swoosh. The air bubble in nike makes it more comfortable for athletes. The personalization that is available for Nike is also what makes it so big along with the major celebrities that release their own style with Nike. Adidas is more affordable and is a better running shoe but is sort of the generic version to Nike.