What is your take on high efficient speakers vs. low efficient speakers?

I use high sensitivity 100db speakers to explore flea watt amplifiers' midrange magic on voices and certain instruments.  The amp is a 8wpc 300B.

I'm not fan of low sensitivity speakers.

For economic and the large number of choices (easier to find bargains), I like mainstream sensitivity floorstanders that can be easy driven by 100-300wpc, extended linear neutral across frequency spectrum, well defined extended bass, sparkling highs, satisfying midrange.  

I have heard quite a number of big, high efficiency systems running multiple 18" drivers (e.g., Western Electric M10, G.I.P. reproductions of M10, Goodman 18" permanent magnet and fieldcoil woofers) and they deliver the speed, impact, and tonality that I think are most important in such drivers.  But, I have never heard these systems deliver really low bass at a high level.  I just don't care that much that they don't do subwoofer stuff and I don't really like subwoofers in these sort of high efficiency systems.  There are compromises in any kind of system one assembles, and these kinds of woofers deliver what matters to me.  Do they measure impressively?  I don't know or care.  I like Rolls Royce's specification of horsepower in the old days: "Sufficient."

I use most all types of amplifiers inc SET with a 6-watt SET I have horns outputting a solid 30hz and getting room lock. Those dissing SET never used them or they SET their system up to fail.

It's just wrong to think that hi eff doesn't do low bass I have bass horns that can bend doors and make your eyes resonate some I designed are used in military simulators to replicate explosions and gun fire. Just because in your limited experience you haven't heard deep bass in hi eff doesn't mean it's not available. It just means you made major compromises in size.

A noob question.

Will a 12w SET be enought for a 95dB sensitive speaker in a 190 sq. ft room if you listen at low to medium levels?