Samsung Galaxy S21 Ultra Phantom Black 128GB

The Galaxy S21 Ultra is a camera beast with a stunning screen and a battery that lasts, all at a tempting used price. But it's a gamble. A worrying number of owners report serious hardware failures like dead motherboards and broken USB ports within months. If you can find one for under $350 from a seller with a solid return policy, it's a steal for the camera alone. Otherwise, the risk of it becoming an expensive paperweight is too high.

Under the hood, the Snapdragon 888 with 12GB of RAM is no slouch for everyday stuff. Scrolling through apps, multitasking, and even some heavier gaming is smooth, and that's backed up by user feedback praising the phone's speed. Our database puts its overall performance in the 72nd percentile, which translates to a capable but not class-leading experience today. You'll notice it's not as snappy as a brand-new flagship with a Gen 3 or Gen 4 chip, but for 90% of what people do on their phones, it's more than enough. The 120Hz display makes everything feel fluid, though it's worth noting the spec sheet lists a 720p resolution, which is likely an error in the data we pulled, as this panel is famously a sharp 1440p WQHD+ screen.

The real performance story here is the camera. It's the absolute best right now in our rankings for a reason. The 108MP main sensor captures an insane amount of detail, letting you crop way in without things turning into a pixelated mess. The laser autofocus is lightning-fast, and the dual telephoto lenses give you genuine optical zoom flexibility that most phones still can't match. Shooting 8K video is smooth, and the ability to pull 33MP stills from that footage is a genuinely useful feature for capturing fleeting moments. It's a creative powerhouse that makes the phone feel fast and responsive in a way that goes beyond just benchmark scores.

Stacked against the Google Pixel 9 Pro XL, the S21 Ultra's camera system is more versatile on paper with that 10x optical zoom, but the Pixel will absolutely smoke it in computational photography and overall processing speed. The Pixel also gets you a clean Android experience with day-one updates, something the aging S21 is falling behind on. If you prioritize a point-and-shoot camera that nails the shot every time and long-term software support, the Pixel is the smarter buy, even if it costs more.

Then you have the Apple iPhone 16 Pro Max and the OnePlus 15. The iPhone is in a different league for video work and raw performance, and its ecosystem integration is a huge draw. The OnePlus 15, meanwhile, offers a more modern processor and that signature fast charging that leaves Samsung's 25W in the dust. The S21 Ultra's main advantage over these two is its potential price on the used market. You're not buying it to beat a new iPhone; you're buying it to get 80% of the flagship camera experience for 30% of the cost. And compared to something like the Motorola Razr Ultra 2025, it's a completely different beast, a traditional powerhouse versus a stylish foldable that makes big compromises on camera quality.

Pricing on the S21 Ultra is a total rollercoaster. We're seeing a spread from $285 all the way up to $1200 across different vendors. At the low end, if you can snag one in good condition for under $350, the value proposition is incredible. You're getting a camera that still embarrasses most mid-range phones and a premium build for less than the price of a new budget device. Newegg is specifically mentioned as a place with a good price, so that's a solid starting point for your hunt.

However, if you're looking at the $1200 end of the spectrum, you need to run, not walk, in the other direction. For that kind of money, you can buy a brand-new Galaxy S24 Ultra or an iPhone 16 Pro Max with a full warranty, a much faster processor, and none of the hardware reliability question marks. The value here is entirely dependent on the price you pay. This is a fantastic deal as a used or heavily discounted phone, but a terrible one at anything close to its original retail price.

The Galaxy S21 Ultra is the kind of phone Samsung built to throw everything at the wall and see what sticks. And honestly, a lot of it did. You've got a massive 6.8-inch screen, a 108MP camera that still holds its own, and that wild 100x Space Zoom that's equal parts party trick and genuinely useful tool. It's a big, heavy slab of a phone at 229g, but that heft comes with a premium build and a battery that can actually get you through a full day. We're looking at a device that was once the undisputed king of the hill, and now it's fighting for relevance in a market flooded with newer, shinier flagships.

Who is this for in 2025? It's for the power user who wants a top-tier camera system and a gorgeous display without paying current flagship prices. The 12GB of RAM and Snapdragon 888 processor are still plenty snappy for daily tasks and most games, landing in the 72nd percentile for performance in our database. That's solid, not spectacular by today's standards, but it's the camera where this thing really shines. With a 98th percentile ranking, the quad-lens setup, including those dual telephoto lenses for 3x and 10x optical zoom, is still one of the best you can get, especially if you're buying used or at a steep discount.

But here's the catch, and it's a big one. The user sentiment score sits at a mediocre 62 out of 100. While people rave about the speed and camera, there's a worrying undercurrent of hardware reliability complaints. We're talking about motherboard failures and USB ports wearing out within months. That's not just a minor annoyance; it's a potential deal-breaker. So you're making a bit of a gamble, trading cutting-edge specs from a few years ago for a price that's all over the map, ranging from $285 to $1200 across different vendors.

You should absolutely skip the S21 Ultra if you value reliability and peace of mind above all else. The documented pattern of motherboard and USB port failures is a red flag we can't ignore. If your phone is your lifeline for work, travel, or staying in touch with family, the risk of sudden, catastrophic failure is just not worth it. Instead, look at a new mid-range phone like the Google Pixel 8a or a Samsung Galaxy A55. You'll get a warranty, modern software support, and a device that's far less likely to leave you stranded.

Also, skip this if you're deeply embedded in the Apple ecosystem or rely on eSIM. The lack of US eSIM support is a deal-breaker for frequent travelers who like to switch between digital carrier plans. And if you hate heavy phones, this 229g slab will feel like a brick in your pocket. A lighter, more modern alternative like the base model Galaxy S24 or even an iPhone 16 would be a much better fit for you.

If you're a photography nerd on a strict budget, the S21 Ultra is a compelling, if risky, option. That 10x optical zoom and 108MP sensor let you take shots you simply can't get on any new phone under $500. For someone who loves to tinker, doesn't mind the weight, and can find a pristine unit from a reputable seller with a return policy, it's a fantastic tool. Just be sure to test that USB port thoroughly the day it arrives.

For everyone else, especially those who just want a reliable daily driver, we'd steer you toward something newer and less of a gamble. The recurring reports of motherboard failure are a dark cloud over this phone. A dead motherboard turns your bargain into a paperweight. If you value peace of mind, a more recent mid-range phone like a Pixel 8a or a Galaxy A55 will give you a warranty, longer software support, and a much lower chance of catastrophic failure, even if the zoom lens isn't as impressive.