A man holds the Apple iPhone XS and XS Max during a product demonstration following the Apple launch event at the Steve Jobs Theater in Cupertino, California, September 12, 2018.

The first reviews of Apple's newest iPhones, the iPhone XS and iPhone XS Max are in.

Most reviewers say if you own one of the older models, then this year's iPhone is a big upgrade and worth the money. But if you already own the iPhone X, then there isn't enough improvement to justify an upgrade unless you want a bigger screen.

Meanwhile, many reviewers suggest waiting for the cheaper, $749 iPhone XR before making your decision on the XS. It offers many of the same features as the XS but has a lower-quality screen and other features to keep the cost lower. Plus, the XR will come in more color options.

Here's what the iPhone XS reviewers had to say on Tuesday:

CNBC's Todd Haselton suggests if you want to save money, wait for the XR.

If you want to save some money, you should wait for Apple's more affordable model — the iPhone XR — which starts at $749 and launches in October. If price is a concern to you, then you really should wait to see what the iPhone XR is like. I only had a chance to spend a few minutes with it after Apple's keynote, but it has the same processor and seems to still have a really good camera, just without things like the hardware zoom lens. It starts at $749, comes in five colors and has a 6.1-inch screen that's larger than the iPhone XS. It's an LCD display, like the iPhone 8 and earlier, which is still fine but just not as good at showing colors and dynamic range as an OLED screen.

CNET's Scott Stein says Apple improved the quality of the camera and photos.

If you compare camera specs for the 2017 iPhone X and the new iPhone XS, you'd think almost nothing's changed: Same dual cameras, same aperture settings, same megapixel ratings, same 2x optical zoom. But Apple's done plenty of work under the hood. The XS has a totally new image sensor that really does improve the quality of photos. The better sensor and the new image processor on the A12 Bionic chip combine to enable what Apple calls "Smart HDR." In practice, that means my photos look better in low light and extreme contrast situations, making for better pictures whether shot on a nighttime street, in a dark bar or in bright sunlight. The larger sensor allows more light in, according to Apple, and I can tell. Focus is faster, too. These elements do a lot to transform the picture quality this year, and serious photographers will be interested.

New York Times' Brian X. Chen used to hate giant phones, but not anymore.

It's humbling to come to you now with another confession: The iPhone XS and the iPhone XS Max may be making me a convert to bigger smartphones. Last week, I began testing both new iPhone models. I had predicted that the larger display on the XS Max would be unwieldy in my pocket and make the phone cumbersome to hold with one hand while typing and reaching for buttons inside apps. After running the 6.5-inch XS Max alongside the 5.8-inch XS through different situations and conditions for a week, I was surprised by my reaction. Far from being disappointed by the supersized devices, I was delighted. The trade-offs of the new jumbo model felt minor. By eliminating the bezels, which are the screen's borders, Apple did a terrific job of increasing screen size without adding bulk or compromising the usability of the XS Max. I still think the smaller XS is a better fit for most people, but many would enjoy the XS Max.

Wall Street Journal's Joanna Stern says the battery lasts longer.

The XS Max's battery life also makes it tempting. It generally lasted one to two hours longer during the day than my X. (As a heavy smartphone user — yes, I'm working on it — I typically charge my X midafternoon to carry me till bedtime.) In my video streaming tests, the XS Max streamed Netflix for nearly 13 hours; the XS lasted 10.5 hours and the older X went just 9.5 hours. But the XR might outlast them all. According to claims on Apple's website, the XR will last 1.5 hours longer than the 8 Plus model — and it's rated to have longer battery life than the XS Max when it comes to internet and video usage. I would also like to note that all these iPhones come with the same dinky 5W charger that's come with iPhones for the last 10 years. Use a faster charger, or else you'll wait hours for your fancy iPhone to juice up.

BuzzFeed's John Paczkowski's daughter isn't impressed with the new iPhone.

My daughter has an iPhone 7. The other day I handed her the Xs Max. She was puzzled in a "Why was this handed to me?" sort of way. I raised an eyebrow. "Oh," she said. "This is the new iPhone. … It's bigger." Then, without a second thought, she handed it back to me, returning to whatever she was doing on her 7. Disappointedly, I said, "You're not interested in the new iPhones? Not at all?" "Not really," she replied. "My phone works fine." Then my daughter suggested that, perhaps, the reason I care about new iPhones and she doesn't is because once upon a time, way back a long time ago when the smartphone universe consisted of nothing more elaborate than … flip phones, I had to use one. Meanwhile, she has known only the iPhone — and other phones that look and behave like it. I thought this a reasonable point. And it gave me pause because I realized my daughter [...] never seen the Fisher-Price phone horror of a pre-iPhone smartphone UI. Apple hasn't made anything transformatively better for her. The world has always been thus.

Nilay Patel of The Verge says Face ID is faster.

Face ID on the XS is ever so slightly faster than the X — just an extra beat quicker. It's noticeable side by side, but it's not so much faster that you won't find yourself pointedly staring at the phone to unlock it from time to time. iOS 12 lets you add a "secondary appearance," which allows you to set up a second person if you want, which is nice. Other than the minor speed increase and secondary appearance support, Face ID is still Face ID: it doesn't work in landscape or upside down or anything like that. If you wear glasses like me, you'll still have to enter your passcode every morning when you wake up because you're holding the phone too close to your face for it to work. And sunglasses that block IR light will still prevent it from working — Apple says it's working with sunglass makers to ship new kinds of sunglasses that support Face ID.

Wired's Lauren Goode says the iPhone's most important new feature is the new mobile chip.