I run an Englehardt EM1 w/ Helicores > Realist copper + K&K Golden Bullet > K&K Trinity Preamp > Warwick LWA 1000 > two Eden 110-8s or a HyDrive 4x10.
I am by no means a connoisseur or expert, but...
I have dialed it in and informally A/B tested it by ear to learn how to get it as seemingly-transparent-to-me as possible, and I have been very satisfied. Sound guys have liked the DI, and more-knowledgeable-than-me audience members have been enthusiastic about FOH results.
I've been using it less as a two instruments doubler (though I may start to do so in another band) than as a foot-switchable option to fit the mix. (The footswitch uses a stereo cable: when I plug it into CH 1, it switches between Ch 1 and CH 2.)
I usually run CH 1 EQ'd pretty darn near 12:00 w/o compressor, and then set up CH 2 with some version of a little mid or mid-high boost (depending on the room) and with a smidge of compression. Then, I use CH 2 for just a slight change of tone to fit the mix. Additionally, with a quick flip of CH 2's mute switch, I can also use it as handy footswitchable mute between songs, to tune, etc.
I also loOove the aesthetics (very '70s home hi-fi looking; the feel of the knobs and toggles), and the Warwick case. I know that stuff is not supposed to be important, but who knows how much it impacts my poor ol' subconscious as I perceive tone, feel confident, etc?
I've also gigged it with electric basses (an ESP LTD B5E and a Squier Jag fiver.) Love, love, love.