is it better to know your tables by heart or understand the process but not have instant recall?
knowing your tables by heart allows you to estimate quickly which is important.
Practicing over and over again with memorization in mind is both boring and counter productive. Instead try activities such as building a multiplication tower. These activities require going through the tables multiple times which eventually will lead to memorization.
Multiplication tower is a beautiful object many people re-discovered for themselves. You can find the history of multiplication towers here: http://www.moebiusnoodles.com/2014/02/multiplicationtowers/
Much better to understand the process! With understanding, you can do mental calculations fairly quickly to get any particular fact---and many other calculations, beyond the basic times table---and you also have a foundation for learning about other topics or for extending the concept of multiplication to other types of numbers (such as fractions). Rote memory, no matter how perfect, has no such growth potential.
The only time rote memory has an advantage, in my opinion, is if you are forced to do a lot of repetitive algorithmic calculations without a calculator---for instance, on a standardized test. Perfect instant recall will help you get through such an onerous chore as quickly as possible, with minimal pain. Of course, if your recall is not perfect, then you have no hope at all.
