I have never had any problem with Lik Sang or Lan Kwei. I have ordered mod-chips and they came well packed in less than a week by uninsured airmail to the UK. There were no installation instructions but these are easily found on the net.
At the end of the day you are talking about a chip which can be broken by installing it incorrectly or even by handling it wrongly (static can kill them apparently). I must admit, when mine didn't work initially, I also thought what a load of shit. But I persevered and experimented and eventually it worked. I must have installed it incorrectly about a dozen times - getting those big red balls and buzzing noises on the boot up screen but eventually it worked (maybe they are not as delicate after all).
I have also bought other stuff from them with no problem - the games are originals and not copies, and the control pads, converter carts, vcd cards, etc. all have worked.
The biggest problem is getting a definitive set of installation instructions for the 64 pin chip. I would post a pic of mine but I don't have a camera. I wonder if I could scan it...