DWS mutual funds are the product of Deutsche Bank, sold through its asset management arm to its clients in the United States. Naturally, its funds run the gamut, from the world of index-tracking S&P 500 funds to specialized municipal bond funds.

You should probably treat bank- and wealth-management-firm sponsored funds with an additional dose of skepticism. As the core business of banking (taking deposits and making loans) becomes less profitable, banks are turning to their wealth management divisions to produce bigger profits. Those profits invariably come from fees charged directly to investors.

DWS mutual funds are expensive
Across the board, DWS mutual funds have average or above-average fees. For example, one of its recent high-flyers, the Deutsche Global Infrastructure fund, had a net annual expense ratio of 1.37% in 2014.

In addition, you'll pay a load of 5.75% upfront to buy the fund's A shares. Thus, for every $1,000 you invest, only $942.50 actually makes its way into the fund. The load ($57.50 for every $1,000 invested) is skimmed off the top mostly to compensate your advisor. You'll need a 6.1% return on this DWS mutual fund just to get back to even.

Its no-load funds also have above-average expenses. Its S&P 500 index fund, Deutsche Equity 500 Index, has an annual expense ratio of 0.25-0.31%, which is almost twice as expensive as the comparable Vanguard 500 Index fund. Higher fees are par for the course when it comes to bank-sponsored mutual funds. 

2 of the top DWS mutual funds
DWS has carved out a small niche in the world of municipal bonds and tax-free mutual funds. Its funds in this category earn praise from Morningstar for performing near the top of their category over long time periods.

The Deutsche Managed Municipal Bond fund has handily beaten its benchmark and its peers, providing a 10-year annualized return of 5.51% vs. a category average of 4.88% per year. It performed particularly well over the most recent 10-year period, having avoided the losses other funds experienced during the financial crisis. Notably, the fund can use leverage to amplify returns, but in exchange, it caps lower-quality B- and BB-rated bonds to no more than 10% of the portfolio. Investment-grade bonds typically make up the majority of its holdings, with its portfolio 98% invested in investment-grade bonds at the time of writing.

Similarly, the Deutsche Strategic High Yield Tax-Free fund has beaten the majority of funds in its category over the relevant 10- and 15-year periods, generating 15-year returns of 5.56% annually versus a category average of 4.85%. This fund differs in that it seeks out a higher-risk, higher-reward balance by selecting among the highest-yielding municipal bonds. It has consistently held half its assets in higher-rated AA bonds, while picking up BBB (the lowest rating for investment grade) and unrated bonds opportunistically.

Mind the mutual fund type
Mutual funds frequently have different share classes with differing expenses, particularly funds sponsored by wealth management firms. DWS employs a number of different share classes for each of its mutual funds. The share class you invest in will invariably have a big impact on your returns. Its high-yield municipal fund, for example, sports a low 0.63% expense ratio on its "S shares." However, its "A shares," most commonly sold to individual investors, carry an annual expense ratio of 0.88% in addition to an up-front load of 2.75%. 

All in all, if you're a Deutsche Bank client, you may do well using its DWS mutual funds for select portions of your accounts -- its municipal bond funds rank quite well. But for other asset classes like stocks, I believe you can find a better deal elsewhere.