Joe,
Basically Dolphin is an engineering program and Vectric is a woodworking / sign making program.
You can draw in Aspire but it has limited CAD capabilities but the CAM side is very easy to learn and very quick.
Dolphin CAD has more capability but I feel it's far too clunky and prefer to draw for both Vectric and Dolphin in a CAD package I'm more at home with.

You get a far cleaner code with Dolphin than Vectric as you can fine tune it better but at the expense of more time programming. Vectric is quicker to program but has this tendency to wander around doing a bit here and a bit there.
for a one off it's not too bad as wasted machining time is far less than the time you would spend programming in Dolphin but if you are producing a series of parts then the programming time is well saved by the cleaner code.

I use both programs equally, quick simple jobs with Vectric and more complex jobs with Dolphin.