I haven't had any problems with my M-Audio BX8a. M-Audio has been good for me.

I also got the BX8a for $300 for the pair with free shipping back when they were selling off the old stock and upgrading to the BX8a Deluxe. Good price. Good speakers. I'm happy.
M-Audio did have a problem with bad capacitors back in the early 2000's back when lots of other companies were having problems with bad caps as well. That may be where M-Audio got some bad reputation.
They are big. They really are big if you're thinking desktop speakers. Get the dimensions for them and make a cardboard box the same size as the speakers. Put that box on your desk where you want to put the speakers and you'll see. Big. I have a big desk and have the room (barely). They're still too big for the desk and a little too close to the rear wall. I've got 4" thick acoustic panels behind them to help tame the rear reflections but it's still not ideal.
The BX8a is also rear ported. You need about at least a foot of space behind the speaker so the port can breathe. Too close to the wall and the port sound changes and the speaker sound changes. So make sure you have room behind them.
Front ported speakers will be easier to deal with. The KRK and Adam (and gasp Behringer) speakers are front ported. You can put them closer to the rear wall. Much easier for desktop placement.
You could also consider smaller monitors and pair them with a sub. 5" monitors are easier to put on a desktop. Much smaller. But then you might be wanting a sub. I don't feel the need for a sub with the BX8a for what I listen to and how I listen.
You'll have to check the manual for your Benchmark DAC1 to see if the balanced outputs are controlled by the volume knob. If they are then you can plug the studio monitors in the balanced outputs from the DAC and be good to go.