I have an arcade and quite frankly I think it offers by far the best value over the Pro.
However, some games (Fallout 3, GTAIV) do have some hefty DLC packs which make use of the Pro's extra HardDrive space, so if you think that that that is an avenue that you would like to explore then you are better off with the pro.
Unless anyone knows ok any alternative ways to store DLC?
Edit
And as for the HDMI cable, they can be brought for R60 from Reggies so its hardly a deal breaker.