gas vs. electric tillers
Choosing an electric or a gas garden tiller depends on the size of the area to be tended, the type of soil and the type of job (small-duty jobs like reseeding a small patch of lawn or preparing the soil of flower-bed; or heavy-duty jobs like reseeding a large lawn or planting large amounts of shrubs...).
The Electric vs. Gas Tillers Option
Gas tillers are more powerful than electric tillers. Even typical small gas tillers have more horsepower than typical corded electric tillers (which are significantly more powerful than cordless garden tillers).
In other words, there is a difference of horsepower in the four types of mini-tillers used in gardening that you should consider when selecting a gas tiller: 1) electric cordless, 2) electric corded, 3) small gas and 4) large gas and propane mini-tillers.
Electric cordless are at the bottom of that ladder, and larger gas and propane mini-tillers at the top.
Obviously, there are also other elements that can and should be considered when choosing a tiller: the price, the noise, the environmental impact, or the maintenance...
Electric cordless vs. electric corded tillers
Electric corded tillers can be a good option for common light and average-duty garden tasks. They demand an outlet close enough to them (which can be a limitation), but they perform well in small and average yards (say less than 150 acres).
They offer some advantages over gas tillers (they are very easy to use and maintain, and lighter and quieter than gas units, and do not emit pollutants). Their prices vary significantly, but are mostly in the range of $100-$300.
As to new cordless cultivators, they are lightweight and very manageable, and their battery ensures a typical autonomy of 20-30 minutes (choose an unit with 18V battery or more). Though they may exceed the expectations of some homeowners (due to their price and lightweight), do not expect too much from these machines.
Even the best units have a limited battery life and limitations on many soils. They work best in cultivated and not too wet, too muddy or clay-based soils. In these conditions, tines can get repeatedly clogged. They have strong limitations, and in some cases they do not add much to traditional or modern manual tilling tools…
Large gas tillers vs. small gas tillers
Even small gas mini-tillers have limitations in their horsepower. They too are designed for average yards: reseeding a lawn patch, planting shrubs, tending areas up to, say, 300-400 ft2 (30-40m2).
Their power output is a step above that of corded electric tillers, but that step can be rather small, and they have some disadvantages: they are more expensive ($200-$400…) and much more noisy and energy-inefficient; and they require the mixing of oil and gas (two-stroke engine units) and, contrary to electric models, are high-maintenance units…
As to large gas tillers, they have some clear advantages but also important drawbacks.
If you need to reseed a large lawn, or if the type of soil of your yard is difficult to break and aerate, and the area to tend is large (larger than, say, 400 square feet/40 m2) then a large tiller can be advantageous... Large tillers have a larger swath width and perform a deeper tilling (prefer a CARB - California Air Resources Board-certified - compliant unit, for a cleaner operation and energy savings).
Just do not forget that they are more difficult to use (they are heavy and bulky), besides being polluting, noisy and high-maintenance. And also expensive, or very expensive in the case of the best models: prices between $1,000 and $2,000 are common, making renting the best option for most homeowners with only occasional needs.
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