I just recently modified my Supertuck to make use of the velcro belt-securing option. Basically, this involves removing the metal clips that you normally attach the holster to your belt with and installing velcro tabs. The tabs loop over the top of your pants and secure to the back of the belt with velcro.
Of course, you need a belt with velcro on it to enable this. I ordered a purpose-built belt from Crossbreed Holsters and have been very happy with it -- it seems to be a quality belt, and it looks nice enough to be dressy as well. ALternatively, the kit comes with velcro you can attach to another belt.
While I was originally skeptical of the concept, I'm actually pretty impressed with how well the setup works. With quality pants that have a stiffer waist line, the velcro tab actually has plenty of stability. I wore the velcro'd holster around all night, including driving, sitting, walking for a fairly large distance with no problems. Stability was excellent.
Concealability was good too. I actually tucked in my shirt (a heavier loose-cut polo shirt on one day, and a thin nylon hiking shirt on the other). The holster tabs securing to the belt are noticeable under close inspection but not something you'd note under casual observation. The tuck actually worked fairly well. The trick I discovered is to tuck everything in tight and evenly, then pull about three quarters of an inch of fabric loose all the way around. "Blousing" the shirt like this mitigates printing, solves bunching around the holster, and also helps cover up the tabs at the cost of looking a bit sloppier.
I wore this setup in a setting requiring deep concealment. Carry was legal but there was a lot of well organized private security that is not friendly to open carry along with some city police presence. I kept a loose windbreaker on (unzipped) and felt 100% comfortable with the concealment setup. With the windbreaker tied around my waist, DW noticed a slight bit of printing as the fabric got tied in close. It required close observation though, and I think most any other observer would just notice an ambiguous bulge (so to speak).
Without the windbreaker there was some bulging and slight printing that could be seen by a careful observer. I think you could get away with no cover garment and a tucked shirt in a regular sort of environment, but given the security presence I wanted to keep low profile. I think a tucked in shirt would work great with a sports coat for more formal occasions, giving a great CCW option instead of a shoulder holster for men in business casual plus attire.
Overall I continue to be impressed with the supertuck. It gets good marks for concealment and comfort.