The OtterBox name is synonymous with ruggedized iPhone cases, but not with battery cases — something the company worked to change with the iPhone 4/4S Defender iON Series, and the iPhone 5/5s Resurgence Power Case. iON aimed to thoroughly protect an iPhone while automating the recharge process, while Resurgence reduced the automation and protection to make daily use easier. At CES this month, OtterBox launched a new version called the Resurgence Power Case for iPhone 6 ($100), and it’s been redesigned with a collection of small but welcome tweaks.

Whether you’ll prefer Resurgence to Incipio’s excellent offGRID Express (review) depends on what you’re looking for — ruggedization or raw power for the dollar. Like many companies, OtterBox is promising to double the iPhone 6’s battery, but it also has some currently unique benefits to offer. Read on for what makes OtterBox’s latest battery case special.

Understanding OtterBox’s trajectory is the key to understanding why Resurgence is what it is. The Colorado-based company built its brand on ultra-rugged cases, but more recently expanded its product family to include designs with reduced ruggedization, successfully expanding its base of fans. So unlike Defender iON, which covered the entire iPhone 4/4s but turned it into a brick, Resurgence isn’t supposed to protect your iPhone against everything. The screen and Home Button are completely exposed — under a hard plastic lip — as are the rear camera, microphone, and headphone port. Consequently, you shouldn’t splash your iPhone with water or dirt inside Resurgence, nor even consider submerging it.

The rest of the iPhone is covered in a combination of hard and semi-hard plastics, including the side buttons, the ringer switch, and the bottom speaker. Most iPhone battery cases feel flimsy or easily damaged, but Resurgence for iPhone 6 does not. You can choose from jet black, gray/white, red/black, and mint green/white colors, which are the only ways Resurgence can keep from looking completely brawny. Thanks to a fiberglass and foam filling, it feels substantial, and worthy of the military-grade drop protection rating it has received.

When a company’s been making iPhone battery cases for a while, reducing the footprint and thickness is a fairly easy task: the developer just needs to choose a battery size and get the charging circuitry down to a manageably small size. As OtterBox is now on its third generation of battery cases, it has achieved size reductions that were elusive in its prior iON Defender and Resurgence cases, most notably cutting the height of the new case’s “chin” down to 0.55″ from the prior Resurgence’s roughly 1″. This means that Resurgence for iPhone 6 is only a little taller than the iPhone 5/5s model, but also thinner, despite holding a 2,600mAh battery inside versus its 2,000mAh predecessor. It’s even a little shorter than Incipio’s offGRID Express, though it feels more solid in the hand.

To accomplish the chin reduction, OtterBox shifted the prior Resurgence model’s small front-facing circular power indicator button to become a larger, recessed version on the back, and moved the prior bottom micro-USB port into a rubber-capped compartment on the lower right. Both changes are welcome, though the USB port’s location means that you’ll only be able to use Resurgence with its included micro-USB cable, rather than a battery case-friendly dock such as Twelve South’s HiRise Deluxe. The four-segment light ring on the rear button lights up all four bars to show that it’s full, and will repeatedly flash only its left bar to indicate that it’s empty.

Resurgence’s raw recharging performance is solid. The 2,600mAh cell it packs is smaller than the ones we’ve seen in Incipio’s offGRID Express and Tylt’s Energi Sliding Case (review), which means that you won’t get the same 120% recharge as with those options. In our first test, we were able to achieve exactly one full recharge with a completely discharged iPhone 6; in a second test, we went from dead to 98% before Resurgence stopped surging. So though OtterBox has designed Resurgence to automatically turn itself off after your iPhone reaches the 100% mark, this will happen naturally with a dead iPhone once the battery runs out; you’ll find the feature more handy if you start with a partially-charged iPhone.

Choosing between iPhone 6 battery cases today is a matter of picking priorities. With the $100 Resurgence, you get a heavier-duty case and lose a little battery life versus the $80 offGRID Express, which offers middle-of-road protection with more battery life, while Tylt’s $100 Energi offers lightweight protection and a big battery. As is frequently the case, OtterBox’s option is the top pick if you’re concerned about accidental drops, delivering greater peace-of-mind. Pick the one that’s best-suited to your needs.