I hope this is helpful
Adam Cherubini, NJ
>Les,
You mentioned three applications: cleaning out dadoes, rabbets and trimming tenons.
I'm not sure how you create these features.
I recommend using a wooden dado plane for dadoes. If you prefer using a router, that's fine. Either way, you don't need to clean up the bottom of a dado. If you use a back saw and a chisel, (I don't) some recommend a router plane of some sort. A narrow skew rabbet might be a good choice for a clean up tool. But since this isn't an essential mating surface, the best tool for the job is the fastest tool.
For rabbets, a S#78 will work, though they are not fast enough for me. A wider skew or square rabbet will suffice for this.
I recommend a chisel for trimming tenon cheeks and shoulders. Believe it or not, planes have a few disadvantages for these operations, especially if you make them by hand. I suspect the shoulder plane was designed to clean up work done by power tools in factories. That doesn't make it bad. Its just not an essential traditional tool, used and cherished in the days of yore. But then neither is the band saw.
All said, if you are looking for a tool just because, then any tool will meet your critieria. There's nothing wrong with that by the way. I have many many tools just because.
I guess my point is there is no one tool for all the operations you wish to perform and the shoulder plane wouldn't be at the top of my list for any of these. If it is functionality, speed, and precision you seek, buy some nasty old rabbets and sharpen your wide chisels.
I hope this helps you choose a tool that's right for you and that you're happy with.
Adam