The Sunfire unit is a great choice where a small footprint is needed.
The SVS is better suited where maximum output, and low frequency extension is desired - with no regard to space constraints.
Both wonderfully engineered units, but comparing these two, is much like comparing apples and oranges.
Sunfire would be the only option if you're trying to bass a small place, and have limited room to do so. SVS would be the best canidate if you are willing to give up some floorspace for awesome bass.
And yes, I have much extensive experience with both units; quite intimately I might add.
Well I should be beaten for my following comments: I dont own the MK but do own the Junior :b I just sold my 17-39PCI and purchased a Sunfire Super Junior sub. Why? Space as I just moved to a smaller home. It is just not fair to compare my Junior to the SVS. Now there are many sunfire bashers here and some of the reasons they use are valid but here is my take for why I made my decision.
There was no way at all to fit anything larger in my new place. I gave up a dedicated theater room for a living room and size was of the utmost importance. Second I wanted something as small as possible but still able to deliver solid bass. Notice I did not say accurate because the Sunfire at average listening levels is highly accurate IMHO ,but when it gets pushed to the edge, it begins to fall a little short. (It also takes some serious patience to achieve a good blend for music but contrary to others opinion it can be done with a Sunfire.) By the edge I mean the distortion levels are almost unacceptable at 26hz and below. I understand though that this is a necessity of such a small design to achieve higher SPL. I will say I am amazed at the how well this little 9" cube delivers the goods but the larger SVS just handles the 25hz material so much better and with far greater ease. My intent purpose in buying the Sunfire was to carry me over for the next year while our new home is being built and it will do that well. The resale value of the Sunfire is rather good and when it is sold I will purchase the PB2-ISD that I have wanted for the past 8months.
A different view from your original question but as my statements show SVS still shines as a bass leader. Sunfire, although a good product just can't compare and this is from an owner of both.
John if my not being an MK owner doesn't help you I will delete my post. You let me know.