The 4GB DataTraveller is my 10th Kingston USB stick. They have all been fast and reliable, the G3s, the best so far. Some of my older, smaller Kingston sticks have now been passed to friends and are over 5 years old. Most are used several times per week, on XP 32bit and Win 7 64bit.
Having read the negative reviews I don't understand why some people are experiencing problems, as I have recently tried other brands such as SanDisk and found them to be very slow on all file transfers, whatever type. Some older Dabs branded ones were also very slow, which caused me to switch to Kingston.
Kingston G2 and G3 from 1 to 16GB all manage fast file transfer rates. The only time they slow down is when handling very large numbers of small files with complex locations, such as copies of web pages I have saved. Whole web pages have many hundreds of tiny files, gif and jpg for instance. All memory sticks have that problem, but I have still found the Kingston ones much faster with those files than any other I have tried and I have tested transfer rates with the same files to be certain. The amount of available memory seems to slow transfer speed, as does doing other things on the computer while transfers take place in the background.
I highly recommend the 4GB G3 DataTraveller as it is a good size for most purposes, reliable brand and very good value at under £5 delivered from some suppliers.