I haven't had any experience with the Tsunamin stuff but I will say Orion. They've been around for so long (even though they aren't the company they were) and I have yet to see a poorly designed amplifier from them. Even their econo "Hott Set-Up" amps from the early 90s were decent.

 

I wouldn't call their "Hott Set Up" gear econo.
Compare prices to the same year Orion competition SX line:
HS 250 $660 ($40 less than a 250 SX)
HS 275 $775 ($40 less than a 275 SX)
HS 2125 $965 ($100 less than a 2150 SX)

They made a lower line also called the "T" line which were on par with the Cobalt.