generally they both line up.

in your case, I would line it up with the cabinet.

How will you finish the edge/end? just a raw edge or a edge trim tile?

I think they should line up with cabinet. You need to be sure you don’t show cut ends. This is from a previous post but they went to the end of counter. Are you are trimming out the window?

I think we are going to go with the schultzer trim (sp?) though there use a bullnose option

No plan to trim out the window there- it’s into a hall so it’s be odd- here’s a pic of the whole space

Planning to take tile to ceiling on backsplash and to level of cabinets under garden window

My designer says it should line up with the upper cabinet.