For live use I'd say that unless there is something actually wrong with the signal (ie. excessive noise, unwanted distortion, cutting low frequencies, etc), very few people will ever be able to notice between different DI sources once the mix gets settled and the show is rolling. Sure, if you're comparing a Noble pre to some $30 bargain basement DI that the venue stores in a milk crate under the stage, it might make a difference. But comparing Nobel to REDDI to RNDI to U5 to Radial to Countryman to Tech 21 to Ampeg to Aguilar to Mesa to ...... you're basically just comparing feature sets and particulars in how they reproduce the tone. I think the underlying quality of the output signal will be essentially the same.
In a studio/critical listening environment, sure you might notice a difference between each unit. Will it matter? Impossible to answer that with any kind of a blanket statement. I've compared the Radial JDI to a Countryman Type 85 in the studio, and while I can hear a difference (when the bass is solo'd and only under very critical listening situations), neither one is necessarily better than the other. If only one was available I wouldn't think twice. The difference between the two is truly negligible compared to the tiniest tweak of any EQ the studio is going to have on hand.
I swore off Sansamps years ago because they had too much of a baked-in EQ that was impossible to get rid of. Eventually I was running my RBI with the Blend dialed back to like 25%... so what's the point of even using it at that point? I hear the same heavy scoop baked into the Darkglass stuff. Some people love it, I personally do not.
The XLR out on my old Ampeg SVT3PRO and current Aguilar TH500 sound(ed) just fine for live use, and I carry a Radial JDI with me every time I leave the house. I also usually have at least one preamp pedal with an XLR out as well... It's nice to have backup on a gig, never know when you'll need it.