before you choose siham, you must know the source it is from. Fresh siham is the best, but the taste differ from region to region
Those siham which is untouched and preserved well in high krass storage will definitely taste gooding.
Some siham you can tell that it has aged in it, thus the taste is abit weird
Some siham have gone through some rather rough handling, not a good choice to taste
Sometimes the preparation of siham is very important too, you need to massage it, best to use some oil and massage it so that the taste can flow out when you lick it.
There are some siham, sometimes only reserved to high krass hotel, which you need a VIP invite. The chef of course is very well known. There will be a parade of few of the best quality siham. Of course it comes with a fee involved.

There are also some unfortunate siham as well tasted by politicians and royalty which almost got these people into trouble.