I have been using the Radial X-Amp for years...flawless!
I preffer active (powered) boxes to passive ones. Everyone said the Radial JDI (passive) was a great DI box, so I got one and it was good. Later, I got the Radial J-48 (active) DI...It blows the JDI away! Active usually seems to sound more clean, crisp and lively to me.
Good luck!
Butch
Let's make some art!