I’d say they definitely are! Especially since you can basically EQ them to sound like anything you want! Also they very likely are the best at reproducing a realistic soundstage in the IEM world, so that does help quite a bit.
As for DAP, the 2 most important requirements are : a very powerful and high quality output, as well as a good quality EQ.
If you have the budget, I’d recommend the Luxury & Precision LP6. It’s by far the best match with i4 in the DAP world. IMHO it sounded significantly better than all the other TOTL DAPs I’ve tried with i4. It’s the only one who could maximize the bass impact and quality while retaining soundstage, air, precision, details and musicality.
Also, although the EQ is only band EQ, it is very effective and the band’s frequencies are the same as the ones for the recommended EQ from Audeze.
If you’re more interested by a more affordable option, you might want to check the iBasso DX300 or DX220 Max. They both sounded pretty good and their EQ implementation is one of the best.
hope it’s helpful!
cheers