Product review (5 stars): Great appliance but isn't maintenance-free
I've had this unit for over 2 years and I'm very happy with it.  I am amazed at all of the folks who think they can buy an appliance and expect not to perform any sort of minor cleaning or maintenance on it at all - especially something like a washer/dryer which you know has got to be getting dirty/linty inside.

I see many complaints about the unit being less and less able to dry clothes after some months of operation.  Since there is no user-accessible lint filter, the lint accumulates inside the air recirculating chamber until it clogs it up and at that point, the unit will start giving you trouble in the drying cycle - at first taking a bit longer to dry, then finally not drying at all.  Luckily, this unit is easy-as-pie to clean out.  I have created a web page that outlines the process, which takes less than an hour:
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In the two years that I've owned this unit, I have had to do this twice.  It's much easier than my previous upright stacked washr/dryer combo (Kenmore) and I don't have to worry about calling a professional to snake-out the duct leading to the outside, which was always a headache because it was a long run and nobody had a long enough snake.

Some things that can make internal lint build-up happen faster are: a lot of drying of throw rugs & things that have rubberized surface, and using too much detergent.  Use no more than a tablespoon of HE detergent in this model!  Most of the times I use only a teaspoon.  Also, this unit has a smaller drum so don't pack it full or it won't dry no matter how clean it is.  2-3 pairs of jeans or 3-4 towels at a time max.

If LG made a mistake when marketing this condensing dryer technology, that mistake is simply in not educating the consumer about operation and how to clean it when it gets clogged with lint on the inside.  Otherwise the dryer is wonderful.