Which stocks are either a fan favorite or a must-avoid? Penny stocks. These tickers going for less than $5 apiece are particularly divisive on Wall Street, with those in favor as well as the naysayers laying out strong arguments.These names are too appealing for the risk-tolerant investor to ignore. Given the low prices, you get more for your money. On top of this, even minor share price appreciation can translate to massive percentage gains, and thus, major returns for investors.However, there is a but here.