I've owned the Two Notes Le Bass, Hartke Bass Attack, Behringer BDI21, MXR M80, Darkglass Vintage Ultra, Darkglass B7k.
I think for value for money the Behringer cannot be beaten. Yes it has a mid-range hole as deep as the Marianas Trench, but only if you set the blend to full.
Honorable mention for the Hartke. Fantastic pedal. Almost out-Sansamps a sansamp!
Fav of the lot was the Two Notes Le Bass. Most flexible of the lot.
I enjoyed the Vintage Ultra, but it's massively overpriced.
MXR didn't leave much of an impression - I still have it somewhere but the DI out is broken. I'll fix it one of these days and give it another run.
Hated the B7k, but no doubt a Darkglass fan boy will be along shortly to tell me I must have been using it wrong...
I'd like to try the Aguilar Tone Hammer. Maybe some day.