My first train set came with a LW. It was able to handle the power needs of my childhood layout and many pinewood central and Christmas tree trains over the years. The power cord was replaced, and I currently need to fix the whistle controller. When I built my first adult O gauge train layout I went with a KW for mainline power. Originally I did it because the KW had slightly more power, but I came to appreciate the second variable output on the KW for controlling accessories independent of track voltage. This was all before more modern transformers became available.
While I don't regret going with the KW there are a couple of things that I think are better with the LW. The LW's simple handle has caused no problems while the KW's knobs have broken off more than once. The LW's simple whistle/horn button is better than the KW's lever. (My KW whistle controller is also shot.) The LW is also more compact. I also thought on my transformers the LW circuit breaker threw more reliably than the KW's but that could just be specific to my particular transformers. Both transformers are currently similar in price.
