I love Xdrip because I can customize whatever alerts I want, with whatever tones I want, and have as many as I want. I know exactly what is going on just by the sound. If my phone sings “sugar, sugar” to me, I know I need sugar. If it sings Chris Isaak’s “baby did a bad, bad thing”, then I either forgot to bolus or over-indulged. I’ve got another very non-intrusive alert (I picked it just because it’s a rising tone, but my husband thinks it sounds like the Jetsons theme song), that’s set at 135, just so I can double-check the amount of IOB is enough. I can also change them at night, so I only get woken up if I actually need to act. Dexcom does NOT give you that freedom. You just set high and low limits.
Xdrip let’s you put your reading in the notification bar constantly. You can always see it hovering at the top of your phone, not just when you’re on the homescreen.
Xdrip let’s you customize your display colors and fonts, even on the widget. Might not be important to some, but I like having it not-ugly.
You can log other data into Xdrip easily, fingersticks, carbs, medications, notes, etcs…
Xdrip gives you better statistical data, in more formats to help you process it.
If you set up the feature, Xdrip can recommend needed grams of carbohydrate or units of insulin to correct. Dexcom can’t.
Xdrip doesn’t share data with Dexcom in any way, unless you choose to link Dexcom follow or clarity into it, so they can’t try to track/outsmart sensor restarts.
The only downside I’ve found to Xdrip is that later versions of Android with beefy security really don’t like apps running all the time. I think OEM Medical apps are able get some sort of security certificate that let’s them run with less bother. My phone likes to put Xdrip to sleep at night when I am, and the phone has been idle, no matter how many settings and permissions I adjust. Sometimes it will stop receiving data and when I wake up, it will say “signal missed 5 hours ago…”, Or something similar. I have to go into the “system status” page, and tell it to “forget device”, then “restart collector” to wake it back up. Rarely, that doesn’t even work, and then I have to restart the phone. I don’t think everyone has that problem, though, seems to depend on manufacturer and their version of an Android generation. I’m running a OnePlus 6 with Android 10.