To me, the only way that the Zio really falls short is memory. 512 megabytes are advertised, but that's TOTAL. It's divided up, as far as I can tell, between RAM (131) and internal storage (186.38) and even then, as you can see, it doesn't add up to 512. People complain about the OS version, but come on. That's software. Even if, for some reason, Cricket never actually updates it (doubtful), the community will eventually bring ROMs from the Sprint version to it. (They're working on it even now.)
What I like about it:
The form. It is a really NICE looking phone. Even better than the Sprint version in my estimation. It's very thin and I like that, too. Feels nice in the hand. I do wish the camera button wasn't so easy to accidentally press, but I've adjusted to it.
The camera itself. While it sadly lacks a flash, the pictures turn out REALLY well when the lighting is right. Video is lovely, too, though you need even more light for that. Oh, and while Phandroid's profile for this phone says differently, it DOES have auto-focus. Like a regular digital camera, slightly press down on the button for a moment before shooting.
The display. A lot of people point it out, but dismissively. I think that's unfair. You will NOT find a display this nice on anything of comparable price. I've looked. And it's addicting. And there are apps that REQUIRE a resolution like the Zio has, particularly some games.
The only thing not so good other than the memory is the trackball. Don't attempt any games or apps that rely on it because it's really terrible. That, though, I can live with more easily than the memory. Mainly the internal storage. It will help once the device is upgraded to a version of Android that will allow storing apps on SD. Until then, I'll deal with it, but it's annoying.
In any case, I think it's a very nice low end Android phone. Trust me, there are others you'd find much worse that you might wind up paying more for.