The knob in the middle (on the amp you saw) might be a replacement knob. Those old Sunn knobs are hard to find, so I'm betting it's a replacement.
$225 usd?
Not to long ago I put my alpha 112p up against my friends Orange Crush 30 watt 1x12"combo (also solid state), and it blew it out of the water. The Orange Crush 30 watt combo sells for $199 brand new.
So I guess if I was in the market for a practice amp, I'd definitely buy that Sunn for that price (if it's in usd).
The only other solid state amp that I've ever liked is the JC-120 Roland Jazz Chorus. It can get pretty loud too.