The following video is part of our "Motley Fool Conversations" series, in which analyst John Reeves and advisor David Meier discuss topics around the investing world.

John and David are always looking for great companies for their real-money portfolios. In today's video, they share their thoughts on three of them.

Small-cap companies offer investors an opportunity to invest in "the next great company." MAKO Surgical, which designs orthopedic surgical robots, might be described this way, since it's serving the big trend of more knee and hip replacement procedures. Another one John and David like is TripAdvisor -- the leading online travel research firm spun out of Expedia. It will probably use its competitive advantage to grow its cash flow for shareholders for years. Finally, there's ExxonMobil, which focuses on returning capital to shareholders in the form of growing dividends and share repurchases.

Experts recommend building a diversified portfolio of stocks. But one thing that investors shouldn't skimp on is the quality of the companies within the portfolio. These three great companies are likely to have a big impact in any portfolio.

The recent market sell-off of MAKO Surgical shares has many wondering whether the potential growth prospects of the robotic surgery company make it a buy today or a stock to stay away from. Read our premium report to read up on the details of MAKO's story. Click here to access it now.