Coming in second, 21.53% of respondents chose the BMW X5, which is not surprising, considering it is one of the most unreliable BMW models. More than 20% of the poll participants thought BMW's first-ever electric car, the i3, was one of the worst BMW models, the BMW Series 5 was fourth in the poll with 17.12%, while the BMW Series 1 came in last with 15.93%.