I have a Samsung steam washer, front loader. I've had it for about 3 years now, and it has never had a musty smell at all. It is a GREAT washer. My previous washer was a Kenmore, and I can't believe the difference - my laundry is about 10 times cleaner with the Samsung. My husband works in construction, he plays rugby, so we have some DIRTY laundry. And then, my daughters are in ballet, so we have all of their delicate ballet tights, leotards, etc, so I also needed a washer that could really replicate hand-washing those delicate items as well. Another thing I thought about was that I don't really love the idea of having to bleach or use color-safe bleach. It's expensive, and just puts more chemicals into the waste water. I love that the Samsung sanitizes using steam, rather than chemicals. (Maybe because I use the sanitize cycle several times per week, that may be why the washer has never had a musty smell, I don't know.) My towels do not have that weird musty smell, even after using them for several days, because they are sanitized when they come out of the washer.
Anyway, I would highly suggest a front-loader - the clothes get MUCH cleaner, with less damage to them, using less water. I've been so pleased with the Samsung, and would happily recommend it. Even though it's a little more than you are looking to spend (unless you buy the floor model, which we did! ;), in my opinion it is worth the extra to buy a really great washer. Think how often you use it!