My Rockboxed clips drive my iems to more than high enough levels with most recordings.
I do a lot of listening unamped but having amp to unload the output stage really makes a difference to the sound, a nice treat.
I guess it depends on what sort of sound people like, as well as partnering equipment, but have never found the clips veiled.
The plus is warmer than the V2.
In the past I have done the PDCP+dac+amp thing and still use an amp on...
Here is a fun thing you can do with an eq/dsp , try to trim things to achieve the apparent perceived effect of a 'trick' ic cable and see how similar you can get them.
I did this with a passive eq a while back..
Regarding the Clip + pitch error , it depends on how sensitive to pitch you are.
It is not something that has consciously bothered me, though i would prefer 'perfect' technical specs.
I believe a rockbox fixes this now, but...