Well first, they get more isolation than I did with the PL-30's I was using (duh). As with many people I think that the ideal size of the tips for me is just slightly smaller than the medium, but since it is a universal, it needs to be able to fit some average, and the fit isn't too bad. Before continuing I would like to point out that I'm not exactly great at picking out details in sound (e.g. I suck at tuning especially tuning violin E using A as a reference pitch).
As for the porting, I've stuck with the neutral bass port since the + port not sitting flush just kind of bothers me (apparently this was not the case with the old + ports). The bass was actually stronger yet also tighter for me with the SA6 than with the PL30's, so this was not too much of an issue. I went with the + treble tip however, since it obviously fits in, although I kept putting it in slightly off straight, but got it after a couple tries. I installed these since many of my tracks are things that I have played in orchestra and I like to be able to easily pick out my part (usually 1st violin, sometimes 2nd).
At this point however, I'm running a Rio ce2100, not exactly the greatest source in the world. However, off of that (I usually run either v0 or c320 using LAME when I rip, but a lot of my stuff is the 192 wma that I got off of a store a while ago) the sound seems somewhat cleaner and not cottony (not sure how to describe it) like I was getting with the PL-30. Taking a stab in the dark as to how to describe it, I guess it would be called a small soundstage. I can tell that the sound is contained within my ear if that helps at all. However, in overall quality I would say that the SA6's would be the best set of phones that I have.