And a limit of only one range extender.
And only 50 devices?
http://www.casetawireless.com/Pages/faqs.aspx
I'll stick with Z-Wave, even though it's not perfect. And it's true that there's some terrible Z-Wave hardware but there's also better (and pricier) gear.
With Z-wave you can pick your hub and devices. If things don't work how you want out of the box, chances are someone has already written the code you need for whatever hub you're using. If not, you can write it yourself.
I am currently using (and pretty happy with) all GE switches with SmartThings hub (soon Vera?), Schlage Locks, Visonic door sensors, Ecobee Thermostats and Harmony remotes for control/automation overrides.
Ack. Please don't tell me this isn't a widely supported thing. powerline communication wreaks havoc on RF spectrum, esp in the HF range.
If you get high quality devices across your whole network, it works great. It's fast, it's reliable, and it'll work over pretty long distances with the mesh networking stuff.
But even one shitty device can bring a whole network down, not to mention that you tend to gamble the first time you buy a device if you are gonna get a good one or not.
Things are MUCH better now if you stick to zwave-plus only as the zwave people are taking a much more "hands on" approach to ensuring that you can't sell garbage with the zwave name on it, and they've added a ton of really nice improvements to the system.
But unless you are just starting out it's gonna be tough to get a full zwave-plus network.
After that, you go with RadioRA 2 and an installer, which is no fun for DIY.