As far as the EOS ROM goes, it is definitely the furthest development of any 4.2 ROM. I would suspect that would equate to good dock support.
Now on EOS 4 and have used it for a bit testing things that I do with my tablet. (you should've seen me swap roms on my gtab if you think that was quick!)
The gripe I had with the dock in the raymanfx build isn't an issue in EOS, the battery is reported properly. When docking the tablet a notification for input shows up, which we're all familiar with from stock, but this one is dismissable unlike stock which is a definite plus.
One of the things I forgot that didn't work was USB, in EOS it works beautifully. The only thing that's irritating is there's a notification saying that it was removed and it won't go away, and it calls the USB drive a SD Card. That last is a detail that is likely an understandable low priority, but that and the persistent notification really irks the OCD part of me.
The "buttons" on the lower bar can be set to reside on the left like Asus did it so halfway there, now if the top bar with notification/clock can get put there to mimic Asus' design I'd be very happy with it. There are quick settings in the notification panel (not shown by default) which is similar to stock, not exactly the same though but functional mostly. If you turn something off in Settings (tested with GPS) the quick setting doesn't change.
GPS, I don't think it works. GPS was on but Maps wanted me to turn it on again. Now the notification for GPS won't go away and it's not actually working in Maps. I don't think it was working in the other rom either so it's a wash I guess.
No "fling" issues noticed yet.
The dock button to turn off the mouse touchpad works, but gives no visual feedback like stock did. Things like that are important, if anyone from EOS is reading this. I'm sure they know but have to say it anyway, for now I'm happy it works.
PvsZ makes sound in this one, but very very quiet. This must be that sound bug everyone was talking about. Low sound is better than none though.
Conclusion: EOS is indeed much better, but it's not quite ready for prime time. Close though, if someone wants JB that's the one to get for sure. If I didn't have need to restore my ICS backup for other reasons I'd probably stick with it even with busted GPS.
edit: Back on ICS now from the aforementioned backup. Know what'd be nice? If TWRP and CWM would play nice together so I didn't have to hack the piss out of my backups just to get them to install. And then there's versions mucking it up worse, where a backup from version X is useless with version Y. We can do better than this.