Depends a little on the mics...
The potential problem with the Audio Buddy is that some people have reported it as not being able to supply enough voltage from the phantom power for certain condenser mics. Unfortunately I couldn't tell you which mics those were. Other people said they had no problem at all. You pays yer money, you takes yer chances.
The ART tube MP and its siblings are generally regarded as substandard as mic pres, but decent as a bass DI. Since I have no experience with it, and kid klash does, I would definitely give more weight to his opinion. I'm merely reporting what I've heard from others here.
Opinions vary on the VTB-1, but it sounds like it would probably work for your purposes. Some love it, some think it's merely average for the money. I don't think anybody hates it, but I could be wrong.
I can't remember anyone disliking the DMP-3, and most who've had it really liked it, especially for the money.
I'd say, if you're looking for a safe bet for vocals, go with the DMP-3 if it's in your budget.
Or, you could try the Tube MP and at that price, if it works, great. If it doesn't you've got a cheap bass DI.
Of course the best thing would be to buy from a place that will let you return it for something else if you don't like it.
Good luck and have fun. (Remember fun?)