Both black hole and antimatter can in principal get you near mass energy equivalent (not better of course), but both have serious technical issues:
Antimatter is much easier. Still it seems impossible to produce with high efficiency (> around 1e-4) because anti-protons are unlikely to emerge from any interaction . Mostly you get mesons which decay away. Once you have anti-protons its very difficult to convert to anti-hydrogen and collect the atoms. Positrons can in principle be produced with good efficiency, but there is no neutrally charged, stable way to store them (positronium doesn't last). Even for antimatter atoms, storage is problematical, One can imagine storing frozen anti-hydrogen or something, but it seems difficult to manipulate, and difficult to cool enough to keep the vapor pressure low enough to avoid unwanted heating.
Black holes are a LOT worse. Small black holes - say the mass of a mountain - radiate a lot of power, but that radiation increases very slowly, then suddenly increases until they explode. The radiation is so strong that there is no way to get matter into the black hole - its gravity isn't strong enough.
Once you get to planet mass black holes you can generate power, but they are rather awkward to carry around (being the mass of a planet!). Its also not at all clear how to build a small black hole. (one that doesn't evaporate almost instantly). Below ~solar mass, kilometer scale black holes, it isn't at all obvious how to get high enough densities.