Features
The Primus EtaExpress has a heat-exchanger pot with strong, folding handles coated in rubber and a lid that doesn’t work well as fry pan or plate, despite the box labeling. It’s too small for those who aren’t ultra-lighters. Plus, it will not stay attached to the pot when packed unless the included stuff sack is used, so plan on bringing the mesh bag.

The pot rests on connected supports that slide into place around the burner. There is no physical lock between the pot and stove, making removal simple. The SOL TI, which has a locking attachment design and no extended handles, can be dangerous to disconnect after boiling. However, the SOL TI’s secure connection is beneficial when cooking in a well-ventilated tent with its proprietary hanging kit, provided you’re comfortable scrambling around a cramped space with pot of scalding doom dangling above you.

Unlike the MSR Reactor and SOL TI, the Primus EtaExpress has a jet that can be cleaned in the field by unscrewing the valve from the mixer tube. Canister stoves rarely clog but occasional stove maintenance is a good thing.

A metal trigger attached to the tube sparks the piezoelectric igniter. This unique design adds some durability because of its quarter-inch steel housing along the tube, but becomes ergonomically clumsy when behind the windscreen. It feels more solid than the plastic push button found on the Jetboil SOL TI. The Reactor lights via lighter or match.

Weight
Minus a fuel canister, the EtaExpress will add just over a pound to your pack. At 1 lb 3 oz., it’s just lighter than the MSR Reactor and heavier than the Jetboil SOL, which tipped my digital scale at 1 lb 8 oz. and 12.3 oz., respectively.

Durability
The EtaExpress is certainly well made. This is important because manufacturers are consistently aiming to be lighter and more compact with tall, narrow pots. At some point in this quest, general durability will suffer. The pot handles are firm and an additional ring of aluminum along the bottom strengthens the heat exchanger fins. The lid, though small, won’t warp under foot, as my 165 lbs attested to. I kicked over the pot, rolled it in gravel and packed it tightly, finding no problems or stress points.

The Jetboil SOL TI fails tremendously in this department. Its heat exchanger fins disintegrated when it was kicked over while lit, I assume because the pot wouldn’t separate from the burner. The plastic stove housing also melted, as did the paper-thin neoprene pot wrap. Furthermore, the plastic bowl/stove base cracked. MSR Reactor showed no unusual wear when subjected to the same stress tests.

Boil Times
I boiled .75 liters of water ten times in calm, sunny conditions. The EtaExpress averaged 3:19, making it a bit slower than the 2:53 averaged in the same test by the MSR Reactor. The Jetboil SOL TI averaged 3:12.

All of those times are excellent, and are essentially equivalent (there is only a 27 second difference in the performance of the fastest stove and slowest stove in our test.) To boil water any faster would be of questionable usefulness in the backcountry, and would require huge losses in fuel burning efficiency—meaning you’d have to simply carry in more fuel.  

Wind Performance
Wind is a large contributor to canister-stove performance. When subjected to a steady breeze between 10-18 mph and occasional gusts above 20 mph, the EtaExpress averaged a boil time of 4:14 over three boils of .75 liters of water. (The Jetboil SOL TI did 3:30 under the same conditions while the Reactor boiled at an average of 3:08.) That’s a significant drop in performance, but not a dramatic one.

Efficiency
The best stoves burn as little fuel per liter as possible, while still producing acceptably fast boil times. The EtaExpress boiled 9 liters of water from 4 oz. of fuel, making it as efficient as MSR’s Reactor, despite the Reactor’s built-in regulator. (With a regulator, the boiling times were consistent near the end of the canister life, but this doesn’t affect efficiency). By comparison, the Jetboil SOL Ti—the most efficient stove in our test—boiled 12 liters on the same amount of gas. It also has a pressure regulator.

Versatility
The EtaExpress is designed to accommodate any kind of pot, not just the one that comes with the stove. Unlike most system stoves that require an adaptor to use a non-native pot, limiting versatility, the EtaExpress allows you to snap on the windscreen and use any other type of cookware you have in your pack. Without the Primus heat exchanger pot, you won’t get the same efficiency, but at least you didn’t buy a stove that can only be used with other members of its family.