[I have non-II version, about 7 years old, but they seem to be the same optically]
This is really hidden treasure in Canon lens lineup. Picture quality is suprisingly good @f8 in 35-105mm range. Not so good @ 28mm, didn't test closely in 28-35mm range
I will be using it on Canon XT in conjunction with Canon 17-40L to cover wide end. I tested 28-105 vs 2 copies of Canon 17-85IS and 28-105 has noticeably better picture quality at most focal lengths.