thepianist65
Gonna seriously consider this as my next upgrade, was looking at upgrading my MOTU interface with another MOTU, but this is intriguing to me. More for the money, it seems. Any comparison with say, MOTU 624 (Thunderbolt 3 and USB 3) or other MOTU devices. Or RME UCX or UFX? Thanks.

Fidelity wise, I'd say it's pretty much a wash between the MOTU 624, Quantum, and Fireface UCX/UFX.
The onboard preamps are also a wash.  All are neutral sounding, will do reasonably well... and are reasonably quiet.
Quantum has zero onboard DSP for monitoring/routing.
Both MOTU and RME offer extensive routing, onboard DSP for EFX/processing, and hardware based monitoring.
Quantum has a very slight edge when it comes to lowest possible RTL.
MOTU and RME Thunderbolt units all have onboard DSP.  That increases RTL by a very slight amount.
MOTU and RME have the advantage of connection via USB or Thunderbolt.  Quantum is Thunderbolt only.
MOTU and RME both offer excellent RTL performance when connected via USB (but not quite as low as Thunderbolt).
 
You really can't make a bad decision with any of the above.
If you absolutely want onboard (hardware based) monitoring... or internal loopback recording, that rules out Quantum.  If lowest possible RTL is a primary concern... and your other needs are simply I/O, the Quantum offers great bang-for-the-buck.
 

I have both USB 2.0 and 3.0 inputs. I prefer to monitor through the DAW. I never use the Presonus software that came with the 44. Low latency would the priority. Although 7.3 really isn't too bad. I guess I could go to 96khz, and drop that a bit also.

I do use the 44 with USB 2.0, and have my monitors and headphones plugged into it. I don't use any outboard gear. Everything is inside the box.
 

MOTU USB drivers are very flexible when it comes to achieving lowest possible RTL.
You can set both the ASIO buffer size and "safety-buffer" as low as 16-samples.
Note that with both set to 16-samples, you won't be able to run much of a load glitch-free.
But you have the flexibility to increase either/both... to find the combination that yields best possible RTL for a given machine.
 
If you're connecting via USB and looking for lowest possible RTL, I'd look to MOTU or RME.
RME is obviously going to be more expensive.
The upside of RME, it's the type of interface that'll last 10+ years.
I'm getting ready to build a machine for a composer in CA who's (still) running a Fireface-400.
He's had it for ~15-years... and it'll make this upgrade (which may take him to ~20-years).
That's amazing longevity when it comes to computer related hardware.

I couldn't afford/justify a RME Fireface 400 when they came out. But I bought a used one within the last year or so and am surprised at how well this thing still operates.

I now see why it costs so much. It's an older unit that has no DSP on it. But the routing options and ability to get low latency when recording is the best I have ever had.

And RME is still putting out updated drivers for it.

Thanks for the response Jim.  I got a pretty good deal on the UFX+, but it was still well more than twice as much as the Quantum, and I do like that I can hook it up to USB 3 in case I ever need to.  Thought crossed my mind briefly to sell it, pick up a Quantum and use the extra money on another guitar... or mic... or well, you know. GAS