Consider stihl. The 4mix is amazing efficient and powerful....nothing else comes close in my opinion!
Straight shaft for more digging power, curved shaft for higher blade speed. That's what I am told.
Stihl FC90 curved shaft $359 (28.4cc)
Stihl FC95 straight shaft $449 (28.4cc)
Both are considered "commercial grade" and will give you many years of reliable service. I personally use all stihl handtools. They last longer, use less fuel, and have more power than ANY other brand available. The ONLY complaint I have is they are slightly heavier than competitive models. Total cost of ownership in 10 years, you will find stihl beats everything available. Just my 2 cents.