Most of those are designed expecting you to use some sort of amplification. But I have had the pleasure to play @ a campfire on at least one occassion with a fellow using one of those & he held up well enough alongside my openback banjo. I was impressed. It sure is a lot easier to tote than a big old "doghouse." Even if you carry a small "practice" amp, they are still more portable than a doghouse.
I don't play base myself, but I too have considered getting one of these, so I would also would like more input on this topic.
Charcloth