United MileagePlus has partnered with Opinion Miles Club and members can earn 300 to 600 miles as a sign-up bonus after joining and completing your first survey. Similar to e-Rewards, Opinion Miles Club offers members miles in exchange for filling out surveys. Before you can answer your first survey, you will need to answer some background questions about your employment and other information.

Bottom line: Opinion Miles Club is an easy way to earn additional miles but not the quickest. The first survey for the 600 bonus miles was about 16 minutes in length but when we looked for additional opportunities, the next survey offered was 36 minutes for only 70 miles. At least Opinion Miles Club indicates how much time you can expect to spend answering questions so you can decide whether the miles are worth your time.