@msommers
I’m eyeing up Pavane L3/Adagio and thinking "will the bass improve enough that it’s worth it?"
I can only speak to my system where I have consistently enjoyed Metrum DACs over others such as Lampi, Aqua HiFi, and Ayre.
To my ears, there is more depth, tonal density, drive, and refinement as you move up the ladder with Metrum. Of these attributes, probably most noticeable to me are the improvements in tonal density and bass impact/depth. Although I found the Jade to sound quite good when I had it in my main system for several weeks earlier this year, there was a definite improvement in the attributes listed above when I installed the Adagio. I should let you know my main speakers only go down to about 40Hz and then pass off to a pair of large subs below that so the deep bass differences may be less noticeable to me than to those whose main speakers handle all the bass duties.
I still own both the Pavane and the Adagio and would say the differences there are close to a wash and may depend more on the preamp you are using with the Pavane. When I first owned the Adagio a year or so ago, I heard a richer, fuller sound from the Pavane through my unity-gain/buffer preamp than I did with the Adagio amp-direct. I have since purchased another Adagio but found to get the sound I want I also had to play it through my buffer preamp. I was able to remove the volume control from the signal path of my preamp and replace it with two Audio Note Silver Tantalum resistors so volume is now controlled solely from the Adagio. For me it is the best of both worlds so I will probably be selling the Pavane soon.