Price wars continue in the exchange-traded fund market as providers seek to gain market share in Europe. However, investors say costs are just part of the puzzle when it comes to choosing an ETF.

At the end of last month, Deutsche Asset & Wealth Management became the latest ETF provider to slash costs for investors by releasing a product that tracks the MSCI World index and has a total expense ratio of 0.19%, the lowest yet for a European-listed ETF offering global equity exposure.