For gas string trimmers, high-tech hybrid engines have taken the choice of two-cycle or four-cycle power out of the equation.

When it comes to gas-powered string trimmers, cutting width, ergonomic features and shaft length are all important, but the most critical choice to consider is whether to go with a two-cycle or a four-cycle (also known as two- or four-stroke) engine. Both technologies come with a laundry list of advantages and challenges, and as you might expect, each engine type has cultivated its own group of supporters -- and opponents -- over the years.

Today, though, you don't need to take sides. Manufacturers have developed high-tech hybrid engines that blend the best characteristics of two- and four-cycle technology. Like hybrid cars, these engines, and the trimmers they power, are initially catching on with a small but fervent group of early adopters. But if the first batch of offerings are any indication, expect to see a wide range of models -- and increased consumer interest -- zip into retailers over the next few years.

Consumer Guide has assembled some of the more interesting early entries into this rapidly growing market. If you're not already sold on a trimmer that relies on a traditional two- or four-cycle engine -- and, frankly, even if you are -- you'll want to consider these new-fangled 21st-century options.

Shindaiwa T2510 String Trimmer

Shindaiwa built its reputation by engineering heavy-duty yet precise tools designed to stand up to toughest backyard tasks, and now the company's phenomenal C4 engine deserves an equal amount of attention. The T2510 string trimmer uses patented hybrid technology to deliver the lower emissions (compliant with not only the consumer emission standard, but also the tougher commercial standard) and higher fuel economy of four-cycle engines with the higher torque and lighter weight of two-cycle engines. And like a two-cycle engine, it requires a 50-to-1 mix of gas and oil, which means you'll have to mix the liquids. This model also features commercial-quality construction and a nifty Speed-Feed trimmer head, which uses an ingeniously simple mechanism to let you reload line in just a few seconds. All this comes at a price, though: This professional-level trimmer has an almost-$370 price tag.

Shindaiwa T2510 String Trimmer

Stihl FS90R String Trimmer

At around $300, Stihl's FS90R string trimmer is nearly $100 less expensive than the Shindaiwa model, but it boasts a similar hybridization of two- and four-cycle technology. Like other hybrid designs, its 28.4cc 4-MIX engine provides the EPA- and CARB-friendly emissions compliance of four-cycle with the efficient power and light weight of two-cycle. It also uses the gas-and-oil mix familiar to two-cycle users, which some may see as a hassle, but it keeps the mechanism's moving parts lubricated no matter which way you tilt, twist or turn the tool. Stihl's low-maintenance design has fewer moving parts than a standard four-cycle engine, while maintaining the low level of noise and vibration four-cycle owners have become accustomed to. This model also features a mix-and-match design that lets you switch the standard trimmer head with optional accessories such as a pole pruner, hedge trimmer or even a mini-cultivator.

Patriot PSSB Straight-Shaft String Trimmer

The 34cc "Fource" engine powering the Patriot PSSB straight-shaft string trimmer isn't technically a hybrid, but its unique design delivers an amount of power that few two-stroke engines can match. The added torque and standard four-cycle benefits (no need to mix gas and oil, for instance, and lower emissions than two-cycle engines) make for a powerful yet efficient combination. The generous 18-inch cutting width is another nice touch. It's not the heaviest-duty trimmer on the market by any stretch, but for the just-over-$200 price, this model still provides a lot of value. Too bad the fuel tank is so tiny (10 ounces!), which means you'll be stopping to refuel more often than with many other models. This model isn't designed to stand up to pro-level use; it's covered by a 2-year consumer warranty, but only a 90-day commercial warranty.

Patriot PCSB Curved-Shaft String Trimmer

The Patriot PCSB curved-shaft string trimmer uses the same 34cc "Fource" engine as its straight-shaft sibling, and it delivers equally impressive results. And at around $189, it's incredibly economical. The engine is four-cycle, but it's specially designed to provide an efficient range of power at any speed, a feature that's reminiscent of a two-cycle engine. It doesn't matter if you're barely squeezing the throttle for light jobs or if you're going full-bore through heavy weeds, there's plenty of juice. The 56-inch curved shaft lets you access hard-to-reach areas or trim tightly against tree trunks or landscaping elements, and the bump-and-feed feature makes it easy to release more line. A small fuel tank, medium-duty construction and less-than-intuitive spool replacement procedure are this model's chief challenges.