First impressions from back to back pours.
Either the Intertap presents lower resistance to flow (and looking at the internals it probably does) or the rougher inner surfaces cause more carb to come out of solution compared to the ventmatics. The pour is faster with no change in serving pressure, and leads to a lot more head with less carb in the beer overall.
There are some rough surfaces in the intertaps, particularly at the top of the spout where it curves down to the thread for the removal spout.
The moving block in the Intertap is a lot shorter than in the ventmatics. The shape is the same, a rectangular block with a cone machined on either end, however the ventmatics block is almost an inch long, whereas the Intertap is approximately half an inch long.
I believe that this has an impact on the resistance which the faucets present to the beer flow and practically speaking means that I'll make up some longer beer lines to get them balanced out.
The stout spout actually poured very well on straight CO2, flow rate issues not withstanding. It does what you'd expect and knocks a lot of the carb out of solution, but it does generate a very creamy head on a pint of stout. Something that will bear a retest with some longer beer lines.
Overall I'm happy with these faucets, I've still got some more work to do but they have made a good impression so far