I think the vast majority of soapers have some of each.
Generally, I use a log. However, I have certain individual molds that I love for their shapes, even though unmolding is a PTA.
If you want to do salt bars, individual molds are a necessity, since salt bars are too hard and brittle to cut without a big crumbly mess.
Individual molds can also be a big advantage if you are making a soap with milk, honey or both, because those ingredients contain sugar which can cause overheating.
Log molds are good because it's easier to gel in them. And they are much easier to un mold.
Currently I have a log mold that holds 4 2.5 lbs logs, a 10" silicone log mold that holds 50 ounces, 2 tall and skinny silicone log molds, a silicone tube mold, several PVC pipes, dozens of pretty individual plastic molds (bought during my early days before I realized what a PITA they were) and several individual silicone molds. I use all of them at one time or another. On my to-get list is a slab mold with individual dividers, and a rectangle vertical mold with a divider.