FWIW...I purchased a next to top-of-the-line, front load washer and drier set about 8-9 years ago. The drier I've never had a lick of trouble w/. The washer has been serviceable, but had to replace the gasket and a door hinge, (both parts and labor covered under warranty thankfully) within the first few months.
At the time the service guy came to replace the defective parts, he gave me the heads-up about the gasket/mildew issue and how to prevent it. His easy preventative to both clean the machine itself and the gasket was the product "Simple Green" which I did regularly. There were 2-3 times over the years where the washer didn't get cleaned for a month or more, and there was a distinct musty smell left in the clothes, but after 2-3 cycles w/ the Simple Green, it disappeared.
Recently, the washer's spin cycle started acting up and clothes were coming out wet. The P&L quote from the serviceman was nearly 1/3 what a new machine would cost, so I told him that I was just going to go that route, and if he had any advice on getting another top loader or not.
I told him I'd been pretty diligent on "cleaning" etc. His response was "yea well" and to ask me if he could remove the door seal and "show me something?" I was really surprised, and actually kinda pissed, when I saw how much "gunk" had still accumulated under and around it. He gave me a crash-course on why this happens, and the pros/cons on top vs front loaders.
I went that afternoon and bought a top-of-the-line, top loader and won't be going back!