I cannot help you anything on Clip + Phonak b/c I don't have Clip. However, I had JBL 200, and I perhaps I can give you my 2 cents on how they compare. Like you, I liked JBL for strong bass and overall musicality, but I finally got rid off it b/c of fatiguing highs. I used to think JBL had good bass for IEM. However, Phonak is in class of its own. It has less bass, but much better quality. It goes deeper and punchier. And, other areas like mid and highs, IMO it isn't even worth comparing. It's like comparing $50 phones to $150 phones.
By the way, my iRiver and Sony has no problem driving Phonak, but somewhere in me thinks Phonak will improve significantly if amped. Hope it was helpful.