While it's true that the Alexa remains more pleasing to the eye, Arri fans seem to exaggerate the differences between it and its rivals. I don't do as much cinematography as I used to but I've seen countless side by side comparisons and played with footage from both. The Alexa is the best but all of the "top of the line" cameras look more similar than they are different. The Alex, Red, F65, and Varicam all produce footage that's quite close. In some ways they feel more like different film stocks from the analogue days. Back in the Kodak vs Fujifilm days, people certainly preferred the colors of one stock over another and some stocks had an advantage in dynamic range or grain/noise. These days you might get an extra stop of latitude or colors that look 10% better on Arri but it's not quite the game-changer that people make it out to be.
Don't get me wrong: There was a period when the Alexa really was heads and shoulders above the rest when it came to color and dynamic range. When the Alexa came on the scene in 2010, it really did look light years above the competition. Sure the RED had it beat on resolution but the Alexa had the "film look" down and nothing else came close. Arri was also a trusted film company and knew how to design a camera which people comfortable with film would be happy to use. It's no wonder the Alexa was as prized as it was in 2010.
But things change. Arri has basically been using the same sensor for the last 8 years (different sizes but essentially the same sensor). Other camera makers have continued to experiment and improve their sensors but Arri has basically stuck with it's "secret sauce." And yes, that secret sauce is still pretty tasty but it's not a league above everyone else the way it once was. The Red Dragon was an impressive step forward. The DP for Better Call Saul (one of the best looking shows on TV), said that the Dragon was the first camera that came close to Arri and, even though he prefers the Alexa, they went with RED because they wanted the smaller form factor. The F65 was also an impressive system that some prefered and now the Varicam is showing what it can do.
On lower budget projects, I find myself annoyed at those who want to spend more than they can afford to get an Alexa even though that money would be much better spent in other areas. An Arri camera isn't going to have nearly the impact that good lighting and production design will. It's definitely not as important as having enough time to properly shoot a scene. Nevertheless, I see films so eager to shoot with the Alexa that they they're willing to cut their lighting and production design budgets and even sometimes cut shooting days. It's not worth it. If you don't have a huge budget and you can get a Red Dragon package for less than half the cost of an Alexa package then I think you're nuts to pay that much more.
The different cameras are different tools. Arri generally has the most pleasing look but I think a false perception of huge differences (as well as the fact that so many DPs are used to it), is a big part of the reason why so many features shoot Alexa. If you can afford to shoot on Arri without compromising other important things then it's a great choice, probably the best choice for most narrative films (even if it does tend to lag behind in resolution). But the expectation of a night and day difference simply isn't accurate.