By far the most straightforward approach. It should migrate most everything(good and bad) for you. If you want the fastest way, this is probably the way to go.
If your current Mac is cluttered up, or not running well, then this option takes all those bad things and moves them to your new Mac.
Not sure what the appeal for a clean install of RW would be. I’m assuming your running RW 7 (going to a new Mac it will be running High Sierra so RW 7 a must). You can move the add-on folder to any location you want. It’s pretty easy to go through your stacks folder and get rid (move to an archive folder) any stacks that you don’t use anymore. Think that’s much easier than reinstalling everything.
I just don’t think in the case of RW that a “clean” install does you much more good than just cleaning up what you have.
I think a clean install on a new Mac is appealing, as it forces you to do basic housekeeping, and get rid of stuff you don’t use anymore. The downside is it can be very time-consuming. I would look at how your current Mac is running as a consideration. If your running trouble free, then perhaps just some manual housekeeping on the old Machine might be all that is needed. After that use Migration Assistant and be done with it. If on the other hand, your old Mac is giving you trouble or is cluttered then a “clean Install” might be the best route to take.