From the perspective of high end audio, where everything makes a difference, from reseating the RCA plug to remove oxide buildup, applying a cleaner, like Caig Pro-Gold to plugs, and all metal to metal contact surfaces. I highly recommend this for earphone headphone contacts, plugs, etc., BTW. This is the cheapest and simplest improvement you can do, with major effects on the SQ, due to removing oxide buildup, and providing a good metal to metal contact. Should be done periodically. This Caig Pro Gold, and a German product called Cramolin (which I cannot find anymore) are the only contact cleaners I found that really work, and over an extended period of time. If you've never tried them, you'll be amazed at the difference a clean contact can provide.
People should keep in mind that discussion and feedback is a civil medium, preferably between people with the same interests. When done positively, the result is beneficial to everyone. Keep in mind that both sides do have the same interest, and keep the discussion positive. Neither side owes anything to the other, and when there is no benefit, either side can walk away. For us users, we all vote with our wallets. Find something that is better, and also a good value, and we will move on to the next "best value".
For me, the DX90 is a blast, as it is offering a SQ that is rivaling DAPS costing 3-6 times more. Yes, the DX90 is not perfect, but it is pretty good for the money, and it is also making music more enjoyable and affordable. For that, I have a lot of patience and forgiveness for the negatives that are present, which I am choosing to live with. Everything is about balance, whether the positives override the negatives. This is true of your work, your mate, your hobby.
Case in point, each fw version has a different SS (Sound Signature). You can look on that as a positive or a negative. On the positive side, you can pick whichever one you like, and that has synergy with your equipment, and use that one. Isn't it nice that you have a choice?
After all, there is absolutely no way to make 100% of the people happy, given this super finicky audience. Every choice has tradeoffs, for the Manufacturer as well as the user. That is the name of the hobby, and I am sure that we each want our own choice. And deservedly so. I want my biases, no matter whether other people believe in them or not.
High end audio is by it's nature imperfect, as we happily change batteries, cables, IEMs, DAPs, Amps.
Look around at your non-audiophile friends, who are not afflicted with this disease. They are supremely happy with their Radio Shack setup, while you are agonizing on DAPS, amps, silver cables, versus silver plated, BA versus Dynamic, hybrids, multi-driver IEMS at ridiculous prices that could be enough for a down payment on a car.
Just remember that you could choose to be like them, happy with a simple setup, with no urge to upgrade/change, or be constantly evaluating the SS/SQ after every change of hw or fw.
But admit it. You are happy with the state of the art, and not having perfection, which you would find boring.
So have a beer ( or a couple), enjoy the music, and look forward to what you can change next.
Me, I'm thinking about paralleling two batteries to see what it sounds like, and whether it is better than the single Japan/China battery (of which I have 3 !), as soon as I am back home in about 2 weeks.
But I am already happy with the way it sounds now, on 2.1, with a Japan/China battery, so I get to satisfy my further curiosity, with nothing to lose. The DX90, paired with an IE800, I am finding pretty enjoyable. More than any previous setup I have had before, so for that, I am happy with iBasso, and the DX90.
pay via paypall! Check first if its in stock 
i got it within 3 days lol thats very impressive for a store in hongkong. Hmm will the malakas in greece deliver it in time for you? 
