As I understood iBasso doesn't need an amp or dac?
(I have an X3 and I would be embarrassed if it needs even an amp!!! (I'm waiting for a DUNU DN-1000 to come: Does need one or I'm ok at least with high gain???))
Only this I can say: they reach in sounding quality the extremely overpriced Apple in-ear phones that they are better than CX-300B's!!!
Both of the last two are given by me to friends and I'm glad I heard the recommendation of headphonelist site reffering to bargain IEM's (less than 50$)!!!
You made a good decision except I don't know much about the reffered JVC or Pioneer.
I have the exact Philips' you bought and I must say that they are very good for their price.
(I am also waiting for the proper Comply foams but I don't suggest them to you if you have a good "seal" with the contained silicon tips).