I recommend the BP factory GMTc (Sead can sell you this, "SuperMirrors" in the TD section) if you ever plan on modding the watch. I have a BP GMTc with gen bezel assembly and gen crystal. I prefer the ICHS as its proven to be more reliable in my personal experiences. There are some who've had CHS movements run for years with no issues. Luck of the draw. I am not to concerned with the ICHS tell as its only evident near midnight which is a non issue for me.