I've never shot a Shilen, but am sure they are just as good as all the others.
I have had 4 Mcgowans and they all shoot and clean very well. My 6br has shot in the .1's and the 308 I just sold to Blue Avenger was averaging in the mid.3 range, with many in the low .2's. I have not had to deal with any customer service either but have been very happy with the barrels I have gotten. My new 308 and 22-250 each shoot 1/2 moa and I have yet to do load work on them yet.

Another option to think about is a Brux from SSS or Sinman.

I wouldnt mind buying a Shilen, but the wait time is just a deal killer when you can get just as good of a barrel in half the time.