How long of a run are you going to have. Are you going to hold cows, calves or a bull?
I've got the cheap one from TSC and it works just fine when I use it. I also have a good ground in a pond. Mostly I use it to keep neighbors cows out of my hay fields. I'd never use one on one of my own fences.
We are going to fence cows and calves out of a new t-85 field that will need tops to make it through the winter. Plot is only 5 acres, but next year we would move the fence to create new t-85 fields...5 to 10 acres at a time.
Skip the solar charger and get regular 12V charger with two batteries. Charge one while the other is in use. I have had a couple of solars, and neither can keep up over the winter due to lack of sun, so you wind up having to charge the battery anyway.