I've had Regulars, had 21's, have a 25, have Tanto's, have Umnumzaan's, and have both the large and small Insingo's, all are great but to me the Insingo blade makes for the best and most useful I've ever owned. I carry my Large Insingo more than any other knife followed closely by the 25, those two have all but put out to pasture my other knives.
That's just my worthless thoughts on the matter, I suggest that you get whichever one catches your eye more. I find the Insingo to be a great looking knife, much sexier than the standard 21 blade in my opinion.
If your budget allows I say get both and save yourself the concern ;P