Consider who you're asking. Do you really think anyone here is going to recommend the Yamaha?

Go ask the same question on a Yamaha forum and I guarantee their answer will be the exact opposite.
I'm sure the Yamaha is a fine bike. The important thing is to do what you feel comfortable doing. Maybe this forum is the deciding factor. We have tons of info and support here. Is there a forum for that particular Yamaha? It's going to need work much sooner than the Triumph. How available are parts?