No they are not all the same. I have a long sleeve shirt made by Ibex and it is buttery soft and never itchy. I also have a less expensive long sleeve shirt made by some generic brand from Backcountry.com and while it is also soft(not as soft as the Ibex) it is noticeably itchy. Not unbearably so as some wool sweaters are that I have worn but noticeably so.

In general, I would probably in the future just save my money and buy from Ibex or Icebreaker.