Pros:
-- If you have never ridden any motorcycle or trike, take it.
-- If you have never had any riding training at all, take it.
-- If your state recognizes the class and provides a DMV waiver if you pass the written and riding tests, take it.
-- If you are on the fence about riding a Spyder and you can take the class on a Spyder, it's a great way to learn if the Spyder is right for you.
Cons:
-- If you've had the MSF two-wheel class, a trike class is 80% redundant.
-- Of the 20% that is unique to three wheels, most of it applies to conventional trikes (which doesn't handle like a Spyder) and sidecar hacks (which REALLY doesn't handle like a Spyder).
-- Of all the possible vehicles (motorcycle, scooter, conventional trike, sidecar hack), a Spyder is by far the easiest to ride. If you already know how to ride two-wheels, taking a class to "learn" how to ride a Spyder is overkill. Even if you *don't* know how to ride at all, the Spyder isn't hard to learn on your own.
Now, I took a trike class and I found it worthwhile. I learned a few good things that helped me on the Spyder (how important weight shifting is in cornering being #1), and after riding an RT all weekend long I discovered that I really wanted a Spyder instead of another three-wheel vehicle, or a new motorcycle.
BUT, again, if you already know how to ride two wheels, I personally don't see a value in taking the trike class, unless you've never taken an MSF-style class before, or it's been long enough that you could use a refresher.
If you don't know how to ride at all? I'd recommend taking the MSF *two wheel* class before/in place the trike class-- after all, you learn on two wheels, you'll be able to ride a Spyder. You learn only on a Spyder, however, and you won't be able to ride two wheels.
That said, the decision is yours. No matter what, training is a good thing, and refresher training never hurts.
