Sorry for the late reply. No. I am not saying the latest batches of E17 has issues. Although I have not heard of the new batch of E17, they should sound the same. Else someone in the forum would have mentioned it. I mentioned I using the original earlier batch of E17 is for your information. Comparing my E17 to the new E17 photos at Fiio website, I noticed that the 4 screws at the back is now allan (hex key) screws. My E17 is using philip screws.
The sound quality is good. The sound quality is better than iPhone 4s but not significant. Below is the setups for the comparison with iPhone 4s.
1) JH16 connecting to E17. E17 is connected to iPhone 4s using Fiio L3 cable.
2) JH16 connecting directly to iPhone 4s output.
The sound quality should be better if the E17 is connected to a laptop with optical cable. I can't test that cause my laptop don't have optical output.
For now, this amp is good enough me. When I have extra cash in the future, I might try out other more expensive amps.