Amp/Preamp Asylum: Digital amps vs. old but good SS stack by Jon T

Haven't read or posted much here in the last few years -- life has a tendency to interfere with audio -- but I was hoping I could ask you guys for some advice. Recently, more and more of my listening has moved from CD/SACD disks to streamed lossless files, for the convenience if not the absolute quality. I use a squeezebox streamed from my computer, which is OK, but needs a better DAC.

I'm debating between adding a DAC to my existing system versus getting one of the new digital amps (e.g. NAD M5 or TacT 2150). My current system is an old but good SS stack: a Plinius M16 line stage connected to a Plinius SA-50mkIII amp. My speakers are fairly sensitive Silverlines, so I don't need a lot of power.

Is there any consensus about the sound quality of digital amps compared to a conventional SS setup? All the reviews of both the NAD and the TacT are glowing, but then 95% of audio reviews are positive... The all-digital route would be a little more costly than just buying a DAC, but the appeal of having just one box is undeniable. OTOH, if it's going to be a step down quality wise, then I'd rather just stick with a system that I know and like. I'm not necessarily looking for room correction right now, but might in the future with either a separate processor or using software on my music server.

To be specific, I'm really only interested in the pure-digital amps out there -- i.e. the ones that do the PCM -> PWM conversion using DSP -- not the many class-D and tripath based amps that take analog input. I'm sure there are great examples of the latter, but it would still require a separate DAC in my setup.