I am disappointed.
 
My US-1641 has a combined signal and overload LEDs per channel. The signal LED is especially useful for quickly finding a channel.
My newer US-1800 only has an overload LED. Tascam dropped the signal function.
 
This new US-16x08 has NO LEDs AT ALL! Nor does it have a monitor mix knob (the 2x2 and 4x4 both do). The maximum input is now only +8dBu, the 1641 and 1800 both handle +14dBu. This overload margin has proved invaluable for drums (and that is after all what these multi-input interfaces are mostly purchased for).

brconflict
In other words, the Echo function shouldn't care or be affected by plug-in delay compensation, because the singer won't be concerned with it, either.  She's going to sing to the audio playback she hears. If the plug-in delay is applied to what's written to disk (to sync the recorded audio to the project) vs. what's heard back in the Echo function...maybe?

 
You do know about the PDC override button? This does exactly this function :)
 

PDC over ride button?

sonarizer
This new US-16x08 has NO LEDs AT ALL! Nor does it have a monitor mix knob (the 2x2 and 4x4 both do). 

I haven't worked with or even seen the unit, but it seems the control application is designed to provide metering, phase switch, solo, mute, DSP, etc. I suspect you'll continue to see this trend to "dumb" hardware boxes with the smarts showing up in an iOS device or computer (I think the US-16x08 application supports Mac, Windows, and iOS).
 
As to the gain, I wonder if that relates to a changed input structure. The 16x08 has enough gain for ribbon mics, the 1800 did not. I don't know if there's a software-switchable input pad like the V-Studio interface has, but I can find out.

Noel Borthwick [Cakewalk]

brconflict
In other words, the Echo function shouldn't care or be affected by plug-in delay compensation, because the singer won't be concerned with it, either.  She's going to sing to the audio playback she hears. If the plug-in delay is applied to what's written to disk (to sync the recorded audio to the project) vs. what's heard back in the Echo function...maybe?

 
You do know about the PDC override button? This does exactly this function :)
 

Right. My experience is using the PDC override function and there's still some delay in Echo, maybe 50-60ms. Even disabling literally all of the FX as well, Sonar still has to somehow process the audio in a way that induces delay when getting the audio back to the ASIO device. It's still too distracting for the singers I've tracked. We always revert to CueMix's low-latency feedback and bring in an outboard compressor to make the tracking more comfortable. 

The only delay involved when using PDC override is the audio interfaces buffer and roundtrip latency. SONAR doesn't impose any extra delay beyond that using ASIO. With a good audio interface running at a 64 to 128 sample buffers, the delay should be imperceptible. Beyond that the only other option is using the direct monitoring feature on the device.
 

Noel Borthwick [Cakewalk]
The only delay involved when using PDC override is the audio interfaces buffer and roundtrip latency. SONAR doesn't impose any extra delay beyond that using ASIO. With a good audio interface running at a 64 to 128 sample buffers, the delay should be imperceptible. Beyond that the only other option is using the direct monitoring feature on the device.
 

Correct. So, with 128 samples even with a 51-sample manual sample offset (ASIO reported latency doesn't seem to be very accurate), recording a vocal track in a 28-track Project, we get drop-outs quickly. Admittedly, I'm using a spinning disk vs. SSD, but this is on a really fast PC running Windows 8.1. Surely throughput isn't an issue. So, we revert to the hardware's own feedback channel and an outboard compressor because it uses a separate software engine and resources. Being able to run the Echo function in Sonar separate from the main Sonar Audio Engine would be a dream.

Let us know the RTL Craig when you get one in your hands.
 

InstrEd
Let us know the RTL Craig when you get one in your hands.

Will do...waiting for the package to show up.

I was just thinking about moving from my us1641 to this new us16X08. So, I am eager to find out more!