Paul White wrote an informative and detailed review of the LCT 640 for Sound On Sound magazine.
Conclusion: "This innovative large-diaphragm mic offers more pad, pattern and filter options than you can shake a stick at — but how does it sound?
My first test was to record a male vocalist who came by to make a demo of one of his songs, and I was immediately impressed by the sound, which, to me, struck the right balance between smoothness and assertiveness; it sounded very polished right out of the box. Minimal EQ was needed to find the required tonality, and the sound remained pristine even after applying a fairly generous helping of compression.
Moving on to acoustic guitar, I was again impressed by the tonal balance, which was solid and warm but with the requisite amount of 'zing' and complexity at the high end. Hand percussion proved to be no problem whatsoever, and the mic even stood up extremely well when miking an electric guitar cab from around 750mm, slightly off axis, where it delivered plenty of bite and depth, but without fizz or grit. The tonal balance remains reasonably consistent across the various patterns, providing you don't get close enough to let the varying proximity effect cloud your judgement.
My main comparison when reviewing this mic was an Audio Technica AT4050. Overall, the sensitivity of the two mics was comparable, with the LCT 640 having a slightly brighter sound. Bright mics often sound gritty or harsh, but there was no impression of that here — the LCT 640 has a great tonal balance and seems to deliver no matter what you point it at. Although it's not a budget mic, I was very impressed with both the sound and build quality of the LCT 640, and it costs rather less than I thought it might."