I now keep stock of a mixture of types of tools, and choose what I think would be most suitable for the job.
But with topaz you have speed of 78 with base + skills, 2400 dura and practically continuous 1 shotting.
Its pretty good, I prefer to sacrifice a little speed to not have to pause for my energy bar to fill as often.
Also note, I was involved in a discussion at some point that, with some testing, it showed swings per second max out at 8.2, even if you keep improving the tool speed.