This isn't really a problem unless the user doesn't pay attention or the installation is a poor one. First and foremost rule is leave the HE front loader's detergent tray and door open between loads. This allows is to dry out. You can also do the tub cleaning cycle (my wife has done it once. I haven't, instead just checking/draining the drain filter basket once or twice a year.) My in-laws don't even leave the doors open and theirs seems to do fine. If the location of the washer is such that leaving the doors open is a problem, then I wouldn't recommend a front loader.
As I've related before the old style top loaders could develop a bad odor as well. I had that problem with a top loader when I lived in Georgia and the utility room was outdoors. A load was forgotten for a day or two once in mid-summer...and that washing machine stunk to high heaven despite various high temp & vinegar washes, mildewcide, etc. I finally cured it by disassembling the tub and connecting hoses and cleaning wetted surfaces by hand. An HE front loader would likely find this sort of outdoor install challenging in a humid & hot climate.
However, the lower volume of water used in an HE means that the resultant washing temp (at least on "hot") is lower because there is a higher mass ratio of tub and clothes to water. Additionally, there is the not inconsequential dead volume of cold water in the pipe. That can make for less effective mildew killing where it is being relied on in hot loads. I doubt this matters much on "warm" because there is some temp. control being done. So for "hot" wash runs it is best to run a nearby tap until the line warms, then start the load. Additionally, there is usually an option for extra water and/or an extra rinse.
If the towels aren't coming out sufficiently fresh from the washer in hot loads, kick up the water heater temp 5 F or so (assuming it isn't limited by a tempering valve at the water heater.)
Our LG front loader is three and a half years old, in-laws Maytag front loader is about 6 years old. I don't miss the old top loader at all. And I like the savings on water/sewer and electric (primarily drying cost which doesn't show in the yellow sticker) from the HE. In fact, I'm at about break even on the cost of the washer with utility savings already.