People have widely differing beliefs about the relative merits of capitalism and communism, and most of the arguments focus on two subjects: people and money. Indeed, both capitalism and communism are philosophies that deal with the relationships between people and money, but they differ greatly in how they express the individual or collective right to money. It may be helpful to think of capitalism as a potentially "all for one" socioeconomic philosophy, while communism is a "one for all" approach.
There are potentially positive and negative implications for both communism and capitalism. Let's consider some of the pros and cons of each.
Some of the positive effects of true communism are equal pay for all, low unemployment rates, and equitable access to free healthcare and education. Sounds great, right? Well, true communism does have some drawbacks. For one, communist societies are highly controlled, which limits personal freedoms and creativity. In a communist society, there's virtually no opportunity for someone who has a good idea to go out, produce, and market their invention. People are limited to re-creating and re-producing what already exists. There are also limitations on how much any person (or corporation) can make-- even if someone puts in more or less effort than another person, they will earn the same wage as everyone else in society. This could potentially disenchant people with their labor and cause them to do less work because they will still receive the same pay.
As for capitalism, it creates a great environment for innovation. Someone who has a good idea can develop and market their invention and if it's a good enough idea, they could potentially make a lot of money. Potential wealth is a great motivator for innovators as well as workers-- ideally, the incentive of increased wealth is enough to inspire a good work ethic in laborers. Under true capitalism, people earn the wage they deserve for the work they do-- no slacking off, here! Capitalism does pose some troubles, though. For example, capitalist societies can create great economic inequality, especially through the devaluation of labor. Certain forms of labor may be considered more valuable than others (farm work versus brain surgery) and the labor of certain people may be considered more valuable than others. Coupling pay inequality with systemic issues like lack of access to health care or education perpetuates a society where some people live much harder lives than others and have no means of betterment. When corporations, which exist as entities separate from the people who comprise them, are offered rights and protection under capitalism, government policy can be swayed in such a direction that it creates a monopoly on certain industries.
Personally, I do not think that true communism or true capitalism are sustainable socioeconomic philosophies. Both may look good on paper, but humans inevitably introduce a number of variables to their enactment. I do not think that communism should replace capitalism, or vice versa, because neither is an effective remedy for the other. Instead, it would be wise to work somewhere in the middle of communism (which promotes equality) and capitalism (which promotes liberties in production.) The two philosophies are not necessarily opposites, but if we consider them to be on a spectrum of how profits are distributed in a society, perhaps somewhere in between the two is a better approach than either "true" philosophy.