What type soil are you on?
If it is like some of the expansive clay soils we have in parts of north Texas I would do deep piers. It is sad to see those expensive brick entryways cracked and leaning after a few years.
Regarding the gate openers I went with solar powered Apollo that has worked well(knock on wood) for the last 3years. Also had a ground sensor added to make exiting easier for guests. I later added a wireless transmitter so we could open the gate from inside the house when guests arrive.
120volts is probably the best solution but it was not an option for me due to distance.
