Need help/advice as an amateur
So I have been looking into FIIO the past month or so. I am torn between the 4GB/64GB JM21 and the M21. Is there really any value to getting the M21? I do like the cassette holder/case for it as it's super nostalgic, but the 4 DAC vs 2 DAC, is it worth a 100+ upgrade. Is the cassette holder more of a gimmick and the JM21 is enough for 95% plus of listeners?
Also, what would be the best all around iem for either of these? I want to spend less that $100 ideally but could go up to $120-$150 if I hold off a little longer. As for my musical tastes, I listen to anything from old big band to classic rock/blues to metal to rap. I have an eclectic taste in music. That being said, I am guessing a neutral sound would be good instead of (looking through research on different IEM types) a V or bass heavy. If I am wrong please let me know. IEMs I am considering are: Zero:Red, Juzear x Z Defiant, KZ ZS10 Pro, Hexa, or EM6L (this is a higher priced than current budget but I have seen good review on this. Also, part of me also wants to get the EH11 for the retro look too haha.
What are your opinions? Any help is appreciated. I have seen a lot of posts, but I want to get up to date responses in case there are any additional factors.