The StockBrokers.com best online brokers 2020 review (10th annual) took five months to complete and produced over 30,000 words of research. Unfortunately, most online stock traders can't tell the difference. To help investors out, we tested brokers and wrote … The 7 Best Stock Trading Apps of 2020 The best overall stock trading app experience comes from TD Ameritrade, one of the largest brokerage firms in the country.TD Ameritrade actually offers multiple mobile apps depending on your needs. First, the basic TD Ameritrade Mobile app gives you much of the power you have on your desktop stock trading app in a mobile experience for iOS, Android, and Windows phones.