After spending much of the past six months at a mediocre three-star rank, Republic Services (NYSE: RSG) has impressed enough top-performing members of our 165,000-strong Motley Fool CAPS community to climb back up to four stars. A total of 409 members have given their opinion on the waste-collection services firm, with many offering analysis and commentary explaining the recent optimism.

Many CAPS members are taking a bullish view on Republic Services. They like the earnings potential of its dirty business of hauling trash as several areas of the economy recover. And major shareholders like Warren Buffet's Berkshire Hathaway (NYSE: BRK-B) agree: Berkshire has substantially increased its stake in Republic in the last couple of quarters, while cutting its stake in other holdings. 

Republic Services has been undergoing some balance sheet restructuring and cost controls, both of which will hopefully help its bottom line and improve its free cash flow going forward. In addition to residential waste collection, the company serves a number of industrial, commercial, and home construction sectors. While investors aren't sold on a strong housing recovery just yet, large homebuilders like Toll Brothers (NYSE: TOL), which reported a 41% jump in orders in the recent quarter, have seen an uptick in building activity. That's giving investors at least one reason to be optimistic.      

Republic Services has also posted improving volume in its cyclical revenue streams, with improvements coming from particular areas like the auto and steel industries. A recent uptick in activity suggests those sectors could be on the mend; for instance, both Ford (NYSE: F) and GM posted double-digit auto sales increases in May. Major steel player U.S. Steel (NYSE: X) reported a 67% jump in overall first-quarter shipments, while AK Steel (NYSE: AKS) saw a 78% jump in shipments.

Trash-hauling competitor Waste Management (NYSE: WM) shares a similar sentiment about the economy. Like Republic, this larger competitor has many active landfills, reported improving trends in its first-quarter volume, and expects to see volume comparisons turn positive in the latter half of this year.      

Do you think Republic Services deserves its raised status? Add your thoughts in the comments box below on this page, or head over to CAPS to rate the company and check out all the information and opinions the community offers, absolutely free.

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Fool contributor Dave Mock recently upgraded his car with a flux capacitor to burn the biological waste he generates. He owns no shares of companies mentioned here. Republic Services and Waste Management are Income Investor picks. Berkshire Hathaway and Waste Management are Inside Value recommendations. Berkshire Hathaway and Ford Motor are Stock Advisor choices. The Fool owns shares of Berkshire Hathaway. The Fool's disclosure policy loves to talk trash.