It's a nice pre-amp with a lot of controls. It works great for both bass DI'ing and microphones. The tube sound isn't all that noticeable compared to my Scarlett 2i4's built in pre-amps, but it does let me push more volume.
I bought this about six months ago for usage with normal dynamic microphones and with my keyboard to give it a bit more warmth. I say it shockingly good as if I pick the unit up when in operation it give off electric shocks! which I imagine is a grounding issue. I imagine it doesn't affect every unit, but be aware as its happened to my unit.
Apart from the fault, I have found the unit to be very versatile and has lots of different settings, for different applications. doesn't break the bank either,