Well, my opinion is that none of these products are needed as a gas additive at every fill up. The gas today does leave something to be desired but if you are riding your bike enough to keep the gas fresh, today's has has plenty of additives, detergents, etc. to keep your fuel system clean.
The problems occur when your bikes sits for a long enough time that the gas gets old. If that is the case, then some type of stabilizer will prevent most problems and you will not get to the point of needing to actually soak the carbs due to them being gummed up.
My bike is now 14 years old. I have never used additives on a per tank basis. I have used various products when I knew the bike would be sitting, for example over the winter. I use one can to a full tank of gas before pretty much putting the bike away for the winter. I usually add one more can sometime in early spring or summer just to make sure anything that MAY have started gumming up is cleaned out and that is it. Two cans a year. Now for the past 5 years or so, the product that I've used has indeed been Seafoam and it has worked just fine. I am sure the Techron work OK too though.
KNOCK ON WOOD...in 14 years, I've not needed any carb maintenance, have not had a float stick, etc. I did pull my carbs a couple of years ago to check and set the float levels and they looked great on the inside.