Using ramps myself with my chevy pickup. Don't have the need for the trailer at this time in the game, as most lawns are less than 6,000 sq ft. You have to determine for yourself if you need a trailer, or if you'd just rather have a trailer. 90% of the time, it will make everything more efficient, but I am falling in the 10%, so will stick with the ramps until the larger mowers are necessary.
The truth is though, if that's what you can afford right now, then by all means, use them!
Good luck with your business.