Greetings, fellow Hsuians.
It's been roughly 6 months since I took delivery of my VTF-3 MK4, and I must say I'm still absolutely in love with this sub. I've tweaked and fiddled a bit since my initial tuning session with it back in September/October, but my opinion hasn't changed on the settings. EQ1, one port, Q of .3 is the perfect crossroads of frequency response and sound quality for my ears. If I want to tighten things up for whatever reason, plug the port. I really only do this on certain musical recordings, and only for them, and only when I'm feeling seriously anal about it. The difference in transient response is audible, and I'm historically a sealed sub kinda guy, but running with one port never sounds Bad(tm) at all. Movies... never run sealed.
In the over-all scheme with my VSX 1120 and Infinity Interlude 10 L/R and 25 C the MCACC settings have the speakers at "Large" and the Subwoofer at "Plus". The IL10's don't quiiiiite make it down to 50 with authority, but the highpass slope on the subwoofer channel that the receiver provides allows for a nice transition. I know THX specs call for the X-over to be at 80hz, but I really can localize bass pretty low and this setting causes 1. Severe narrowing of the soundfield (staged music or movies) and 2. Too much boom in the 60-80hz range. This second thing is not any fault of the sub, but rather the meager EQ ability on the sub channel of the receiver. It's importance is completely mitigated by point 1 though: I hate the way it sounds when the mains can't do some of their own heavy lifting.
If I had the room to run two of these things wired for mutual stereo and LFE... I totally would. That's not going to happen though.

I know I'm talky as all get-out when I wade into this thread, and today's no exception, but for the review of material played through the sub in the last six months, it's a very short discussion.
This sub plays everything well because it just gets out of the way. This is especially true on EQ1, sealed with Q of .3. Get the levels dialed in and this thing does for the bass material what a solid tweet does for the highs: it doesn't dictate the material, it just puts a shine on it. Bass can indeed be breathy and delicate, even when it's pounding your head into the walls. And this sub does this through all levels of dynamic range, and all without any sign of strain from driver compression, lack of amplification ability, anything. It's just clean. Very, very clean.
When you open up one port, changing nothing else, the character does change as described above, but because of the protective nature of the extremely low port tuning, the lack of strain even down to 12hz in my room is just staggering. If you've not experienced the solid presence of below-20hz material before it may actually startle you at first. I HAVE been around that sort of material for decades in cars, and this still startled me. I've never heard reasonably accessible (from a financial perspective) home subwoofer solution that could do this, and it does it so well that it's just jaw-dropping.
In closing I'll provide a quote from my wife from this past weekend. She'd gotten me the Imax Hubble Telescope bluray for Christmas, but we'd not thrown it in yet until Friday night. There are two shuttle launch sequences in the material. The first one was from years and years ago, and the recording mechanisms used weren't so good. The second one though, was recorded in high-def glory with excellent sound back in 2009.
As a kid she was present for a shuttle launch. When the first one on the bluray played, she commented immediately that "wow... should be more bass than that" and kinda frowned. We both just kind of shrugged and kept watching, changing no levels or settings.
The second one went off later in the material. The whole room sounded like it was going to come apart at the framing and rip itself from the foundation. Once it all subsided, her eyes blinking in amazement, "
That... is what it really sounds like."
This sub is just disgustingly good, and you can tune it to sound as beautifully clinical or diviantly quake-ish as you like. And in my house I can do this in ~4000 ft3 at ridiculous reference levels at the seating position with room modes of 120+ db @ 16hz.