I have their 13" planner with the spiral head cutter and love it. Only downside is I have 2 cutting edges instead of 4 but it works great. As for the jointer, I always go for larger if at all possible because it's more capable. I have a friend that has a 6" Delta that has been lusting after my 8" Powermatic D60.
The other thing to keep in mind is that the planner can be used to flatten a wider board but it's different than just planning it down. Typically I see a sled and shims being used and it takes some real practice but can be done. A jointer will do it faster, again, if you know the proper usage. But then you can always fall back to the "old ways" and hand plane a wider board flat as well with a jointer plane or a jack plane. More work but good results and no having to cut the board down to fit the machine and glue back together. Something to think about.