If you see the word rototiller in a landscape specification, be suspicious. There is no tiller on the planet that I know of that will adequately penetrate the compacted urban soils of todays constructions sites. Compacted soils must be deeply scarified or incorporated for them to do any good. Even if rototillers could get partway into the soil, they would then leave a slick interface difficult for roots and water to penetrate. A backhoe with a good operator make short work of compacted sites, fracturing and slightly mixing the soils with top organics and not overmixing, not destroying PEDS in the soil, something else rototillers destroy. When aggregates are bound together into larger masses they are called PEDS. Peds are naturally occurring units in soil structure that develop over time, important for plant growth and soil health. In otherwords, preserve the PEDS while breaking up the compaction! Use a backhoe!