If proponents of SIP are able to maintain that the SIP system has advantages over the swick system, we should be able to demonstrate the reasons why.
You sound a bit defensive with that comment, but I'll tell you why I prefer SIP.
I have had consistent success with my SIPs which I've built from 9oz up to 14 gallons, but had variable results with the SWICKs as I found it a challenge to match the wick sizes to the plants as they grew.
I like the single pot, self-contained set-up with SIP, at least the way I build them vs the separate container for the reservoir with the connector thread between them.
I prefer the action of a soil wick rather than a synthetic one. The rope wicks promote a constant and steady flow of water where the soil seems to act more on capillary action by simply replacing moisture that is used or evaporated.
I'm confused as to why a pot sitting in a bed of perlite which extends above the water table doesn't have an air gap. Yes the perlite is wicking water but is there not enough air amongst the perlite bits to be considered an air gap? Does it need to be just air to fulfill that "requirement"?
As I stated in the other thread, there is a material difference between an air gap and air between particles of perlite. In the latter, as Emilya stated, the roots will populate the petlite layer as long as there is moisture to be found. This is quite different from the air pruning that occurs with a true gap. The air pruning promotes a different root structure further upstream vs the water seeking roots that continue on down to the reservoir.
My interest is in the explosive growth the SIPpers are finding. I am specifically interested in soil grows. I'd like to know if the roots develop in the same manner in SIP and swick, and if they do, shouldn't there be equivalent explosive growth potential on a swick?
Probably yes if the wick and plant size are matched correctly throughout the grow.
I argue that the dry perlite layer is an air gap. I don't understand why Azi does not consider it a proper air gap.
The dry perlite layer provides air, although not as much as a gap, but does not have the air gap qualities that I think make it superior.
I agree with the others that a side-by-side with clones would be a better way to answer your questions but I don't think it matters all that much. Both styles seem to grow good plants and we each have our preferences for the various different factors.
So, pick and choose from the various styles and grow your own grow. There are now many different build variations that have been posted that one should be able to find something they like to get started.