Why are you so surprised? I haven't had any lag whatsoever in Mango either. It does seem odd that many of the problems being reported are by new-ish members. Perhaps the batch that you guys were sent was a bad batch...?
I'm aware that some people have had problems with their devices, but there are so many people here that it's difficult to separate the different issues. I am curious when the batches with lag appeared? I use Mango exclusively and find it to be great.
Have a look please what I basso says itself regarding to the last FW:
1. Rectified the bug that when charging or in sleep mode, the DX200 has a small possibility to reboot.
2. Rectified the bug that sometimes when playing music, the DX200 automatically pauses or the Launcher crashed. (Android OS)
3. Updated the playlist import and export function.
4. Rectified the bug in the first minute of using the DAC function, the DAC might disconnect from computer automatically.
5. Rectified the bug that system error happens when using the Japanese input. (Android OS)
6. Rectified the bug that when playing some APE music, the tracking number showed as 0/0. (Android OS)
7. Rectified the bug that when playing DSD music, pressing the tactile buttons would introduce noise. (Android OS)
8. Rectified the bug that when playing from Directory view, the Now Playing track order is different to the track order of theDirectory view. (Android OS)
9. Rectified the bug that when playing some DSD music file, the sound stutters. (Mango OS)
10. Rectified the bug that when playing some specified music format, the system becomes slow to respond. (Mango OS)
11. Rectified the bug that when playing some CD image or ISO, the album artwork can't be displayed.
12. Rectified the bug that when playing from Genre view, and returning from secondary structure, there is nothing displayed.
13. Updated FLAC decode engine, and improved FLAC support.
This is very unique that manufacturer states clearly about the bugs and some of the clients are suprised not observing any deviations. People are different, but I would not devide them into new-ish or old-ish members.