You don't always need the best, but you do need accurate. I've had machines with lousy feed dogs and wondered why i couldn't sew straight. Some rotary tools could also be off. I'd say buy something from a shop or outlet that has a decent return policy. If it's a large expense - test it first. Don't buy from a friend's recommendation unless you have played with that friend's machine first and you like it. There is also nothing wrong with a second or refurb that comes with a warranty.
I learned to do applique, cutwork and some heirloom on a zigzag machine. Takes more patience, but can be done.
I've seen ladies buy a TOL sewing machine with fantastic capabilities, only to just embroider. A six needle was in the same price range. A TOL doesn't always suit everyone's needs although sales people think so.