Not a bad price, i think the make is Royal but i would have my doubts as to whether it would be any good in heavy soil
http://www.selections.com/GF9178/5hp-petrol-tiller/
It should be OK for heavy land, I use a Wolsley Webb Merrytiller Major with a 4hp engine and my land is heavy clay, and it digs to 254mm deep.
It's strange, I have recently bought an Einhell 3336 Petrol Tiller which very similar characteristics. The engine looks to be the same but with slightly different fittings. It is a 4.5hp engine, but the main difference is that the Einhell digs to 23cm (9") deep instead of 120mm (4") otherwise it looks to be the same machine, even to the same plastic moulding on the handles where they bolt to the central column. The Einhell was £230.