Boolean operations aren't necessarily cheap, but they do require one thing: tact.
Every program is different, and the performance of the boolean operations for each are imaginably unique to the respective program. I find the most effective operation in AC3D to be the "knife" operation whilst making a backup of the original cut section so as to ensure the accuracy of the new cut. Then it's a matter of cleaning up the cut area: re-combining surfaces, deleting extraneous verticies, etc. When I'm done, the results are perfect, but it takes a little effort to get there. Personally, I like booleans as they enable my perfectionism to work, albeit with maybe just a bit more effort.
Practically applying subdivisions, now, is an art!