I have used the heat transfer method extensively in the past, and will probably return to it in the next couple of months as I test new recipes and such. I LOVE the heat transfer method, as it does save the extra step. And you can ask anyone how much I love that! However, it only works well with certain oils/fats. I do not like it at all with butters or waxes (which I rarely use anyway). I use primarily lard, which is soft, and CO, which melts at a low temperature. For those, it works a dream.
I have mostly been masterbatching oils for efficiency here lately. Get a big old stock pot and throw 4 or so batches worth of oils in there, then weigh out each batch into its own bucket. I typically do this the day before soaping. I masterbatch my lye also, as well as my additives. So, on soaping day, I use V amount of colorants + W amount of FO + X amount of oils (premeasured) + Y amount of lye + Z amount of additives. Works a charm, and allows me to concentrate on design. And yes, that is the order I measure them out. I put the oils in the microwave just long enough to get clear oil, then while it is zapping, I weigh out the other ingredients.