i honestly cant recall as I was messing around one day w/ 2 diff rasp pis 256/512 and openelec, raspbmc and rasplex.
I had and a Buffalo n adapter I think that was frustrated with raspbmc and rasplex didnt work but works just fine w/ openelec...except that on bootup i have to cycle wifi on/off or replug it in.
I also couldnt access any if the SID was hidden even though open some would know it was hidden and attempt to let me logon, i couldnt.
Its a bit odd since I think at least rasplex uses openelec as a base.
Which version of Openelec does you dont work with ?
RasPlex is using the OE 3.2.2 codebase. Should it work there it should work on ours as we have no patch in the OE kernel ... that is pretty strange.
Should it work in higher versions of OE, then you might have to wait for a bit longer. After 0.4.0 is out, the next big step is to move to Gotham which means OE 4.0. That new OE version is supposed to bring a much better driver supprot because it has a more recent linux kernel.
ChromeCast is cool ,though it has nothing really to do with Plex Client in any ways, there is no GUI, you need a good PMS server as it needs a lot more remuxing / transcoding.
Personally for the same price i'd rather stick with a RPi :)