It seems that bypass pruners are recommended more often than the anvil type – are there any times where the anvil type are better?
The majority of gardeners do seem to prefer the bypass pruners. Closer, more precise cuts are possible with bypass style shears. Cuts are also cleaner with less chance of crushing stem tissue as sometimes happens with the anvil style pruners.
Anvil shears, on the other hand, can take a larger bite without springing (bending or spreading the blades apart). Double-levered anvil blades are often used for lopping shears (long-handled pruners for cutting larger stems up to 1-1/2″ in diameter or more). Anvil blades adapt nicely to ratchet-style pruners, as well. Ratchet pruners have more strength, but require less effort to operate, making them ideal for arthritic gardeners. Also, anvil pruners are less expensive than the bypass type.
Whichever style pruner you choose, never try to cut branches larger than intended for the tool being used. Most hand pruners should not be used to cut branches over 3/4″ in diameter. Loppers should be used for stems up to 1-1/2″ or so. A pruning saw is the best choice for larger branches.
Always keep your cutting blade sharp. Many better pruners are constructed in a way so as to allow for blade replacement should it become nicked or badly worn.