The TransNova Haflers were designed by Jim Strickland of Acoustat, not David Hafler and those Acoustats (TNT 200 & TNT120) were great amps. I would take the Hafler over the Yamaha all day…..
But another amp that I really like at 1/2 the price is a B&K EX442 or 442 Sonata. Very powerful and tubelike.