I just bought a Shamrock 23ws around 6 weeks ago, from Pgh area to Cincinatti to get it to save 3 grand. I am a retired Auto tech and am quite fussy about my campers, (I had a Kodiak hybrid before this one) I must say I am VERY impressed with my Shamrock, I am taking it out for the first trip this weekend, I have been "back yard camping/modding" in this since I bought it and am very pleased with how well it tows and with how it is made, Are you getting a new or used 21s? just wondered.
Good luck!