Regarding the planer, I’d say get a lunchbox type unless you plane/mill all your own wood, and plan on doing a lot of bigger pieces. Lunchbox planers have been good enough for me and many others. If you have the room and money, though, go for it.
Also, to each their own, but I find cutting dovetails by hand is a better way to learn about the joint. If you’re plunking down 350 for a jig, you might as well get a couple real nice chisels and a saw, and save yourself a little cash. Maybe you already cut your own DTs by hand and are looking to expedite some sort of mass production, but I find I can cut a joint in about the same time it would take to set up a jig for the scale I work on. That said, if you have cash and space in your shop for a jig, and it interests you to use one, go for it.
-- Bailey F - Eastern Mass.