I have two GT-700s and a GT-500. I think the 500 is the best bang for the buck. The profiling feature is not something you want to get all worked up about because it won't profile a pick-up, SUV, or a minivan. Have you ever seen any of those on the road? The 700 can be programmed to do a wash a little faster than a 500, but at a cost IMO. It puts out the wax and SFR with LP arches whereas the 500 uses the HP pumps. I speed up the wheel speed on the 500 for the wax and SFR and put them both on at full pressure. I know this may be a waste in many people's minds, but it sure makes the wash process more impressive to the customer.
As far as speed programming, the 700 has 10, the 500 has 4. The 500 only having 4 has not been an issue. Frankly, having the car chopped into 3 zones with 10 speeds per zone (major overkill) can drive a man to drink.
I don't own a 300 so I can't pass an educated opinion on it.
