Good to be discerning, but don’t over think or worry about your potential selection. Either are a fine enduring choice!
Basically AVENGER = MANFROTTO products in so many of either’s product line. Marketing channels
Both are durable, stable & great quality products which will likely outlive you!!
Really comes down to how much you value the convenient leveling leg feature on the Avenger (marginal benefit vs marginal cost), preferred folded length and how much weight you want to pack; which only you can answer.
It appears a lot of photography stuff is about the marketing, (like other industries, such a marine/yachting stuff, etc.).
i.e. Single manufacturer with multiple marketing/distribution channels & multiple geographical markets.
Just an FYI - the referenced clip/lever to tighten/loosen the legs on my four MANFROTTO 1005BAC’s have never been a problem after many years of extensive use (including supporting 4 Profoto D1Air-500 monolights with various Profoto light modifiers). In fact that clip/lever enables very fast setup/take down when dealing with dynamic situations.
Good luck with your selection.
P.S. I own a lot (sshhh… too many to admit to) of AVENGER, MANFROTTO & MATTHEWS(MSE) supports and vast variety of each “brands” hardware, ANY & ALL of which you can count on; are great and will withstand many many many years of use both in & out of studio including harsh environments and applications.