So Many questions
I have the ES100 and the BTR5,  Loved the ES100 software,  not so much the BTR5 software,   I have so many questions:

SpecFiio BTR5Fiio BTR3Earstudio ES100Qudelix-5K
BT ChipCSR8675CSR8675CSR8675QCC5124
BT VersionBT5.0BT4.2BT5.0BT5.0 ?
FormatSBC、AAC、aptX、aptX-LL、aptX-HD、LDACSBC、AAC、aptX、aptX-LL、aptX-HD、LDAC、LHDCSBC、AAC、aptX-HD、LDACaptX Adaptive, LDAC, AAC, aptX-HD, aptX, SBC
USB InterfaceXmos xuf208CSRCSRCSR ?
PCM384k/32bit48k/16bit48k/16bit96k/24bit
DSDDSD256 NativeNoNoNo
FPGA (For digital audio)YesNoNoNo
Dual audio clock45.1584M/49.152MNoNoNo
Audio DACES9218P*2AK4376AAK4375A*2ES9218P*2
Volume Level6032asyncAsync
GainH/LNoNoNo
3.5mm HP out80mW@32Ω25mW@32Ω35mW@32Ω???????
2.5mm Balanced220mW@32ΩNo100mW@32Ω????????
SNR(A weight)121120110????????
Indicator&DisplayMatrix OLED 64*32RGB LEDDual LEDRGB LED
Line-control (Line-control)YesNoNoNo
USB typeType CType CMicro BType C
NFC LabelYesYesNoNo
Battery550mAh300mAh350mAh500mAh
Working TimeSE: 9h11hSE: 14h20h
MaterialAluminium alloy+GlassAluminium alloy+GlassPlasticPlastic
APP controlYesYesYesYes

Can anyone fill in the blanks ???
Qudelix
Please check the below:
https://www.qudelix.com/learn-more-1

Both devices are the most functional Bluetooth and USB DAC.
You will need to study every detail and pros/cons, before you make a choice.
After going through the link above, let us know if you still have any further questions.

Thank you,
Qudelix
cool thanks for the reply,  did that and my most immediate question is can we connect to two Bluetooth devices at the same time ?    
Qudelix
Yes, 5K supports the multi-point pairing up to two devices.
For example, you can have 5K paired with a laptop and a smartphone at the same time.
(We'll add the page for multi-point pairing shortly.)
Thank you.