Any thoughts?

You mean, apart from, I'd be pretty ticked off?

The Netgear PTV3000 works fine as a Miracast. Used it for months now, every working day, to make my Venue 8 Pro as my "main computer" and leaving my heavy bulky work laptop at home. But Dell announced the dell cast dongle. http://www.citeworld.com/article/2604009/consumerization/dell-launches-dell-cast-a-chromecast-for-business.html While the news article doesn't detail if this is a miracast dongle, it likely is.

But I'm not quite sure I see the advantage over a DV8P set up with a PTV3000.  Although, I guess that you can have a separate keyboard and mouse for what is on the monitor and operate the monitor's screen from those rather than having to use your tablet?  Or I must be missing something?

Just to provide an update/summary that may assist others, as Dell and others here have assisted me:

I just purchased and set up a PTV3000 with a Dell Venue 8 Pro, and it ultimately seems to work well.  But there were initial, painful hiccups:  (1) the PTV3000 would not mirror the tablet display but instead only would allow extended screen use; and (2) every time I would start the screen-casting, my tablet, in landscape orientation, would re-set to portrait view and would not change. 

Answers:  (1) from the Dell Venue 8 Pro updates/downloads webpage, make sure that the Intel Platform Driver Installer update (the latest, released Dec. 2, 2013, is Version 603.9600.2067.26305,A03) is installed--it fixes the display mirror issue; and (2) use the tablet's Intel HD Graphics Control Panel Graphics Properties/Display option (available in the Windows 8.1 Notification Area or by right-clicking the Desktop; you also may be able to do this via the Intel HD Graphics Control Panel Graphics Options/Rotation option) and set the Rotation to what you want, in my case 270 degrees for landscape orientation--the trick seems to be, using the Intel HD Graphics Control Panel for this, even if the orientation had been set previously (mine had been, to the same 270 degrees--I simply chose a different degree setting and then the 270 degrees setting again, and then clicked Apply), so that the orientation setting "sticks."  

The only issues I have had thus far in use, having worked out the above issues, are the PTV3000 monitor option once disappearing (reason unknown--perhaps as a result of many hours of use?) from my Charms/Devices/Project monitors listing--I simply added it back, as is set up originally, through that section's "Add a wireless display" easy and quick option; and be aware that if you select the "Second screen only" option so that your tablet screen goes blank/dark while the content being played is on your TV, it can be difficult getting out of that mode without using a mouse (wired or wireless) as versus pure tablet "touch" mode, as one likely would want to do--Dell has explained that a "trace" shows in that mode, to assist in knowing where the cursor is so as to be able to call up the Charms bar to disconnect the content-casting or choose a 2-screen option when done with the content, but I haven't been seeing it, and so have not been using the "Second screen only" mode (when I catch my breath, I'll try experimenting some more--perhaps using the tablet's physical Windows button would assist?). 

But now with these issues worked out, it is a joy to easily cast an Internet video or stored content file from the Dell tablet to the TV.  Perhaps the summary of these tips here will help someone else, and save you the getting-started pain I had.

I had some better luck today. I updated various drivers from the Dell site. I assume the most significant was the Wi-Fi driver. Now I'm able to connect to both the Actiontec and Netgear PTV3000. But the display is only in extended mode - clone mode curiously doesn't work. And extended mode on a tablet is not very useful as there's no way to move the cursor over. Let's see if upcoming patches help. I'll keep trying.

I ran into similar trouble and found by running dxdiag (and saving the full results to a text file and searching for Miracast) that the WiFi driver isn't compatible with Miracast.  Since it is listed as being Miracast compatible in a couple of places on the product description I felt obliged to call Dell support and let them know. 

Through research I have found that the WiFi driver that Dell has made available for the hardware is not NDIS 6.40 compliant, so hopefully they can provide a simple driver update to make this advertised functionality work.

Same problem too.  Can only use extended mode which makes it useless.  I hope they get some drivers updated soon, or I will have to return it as I bought it for the primary purpose of using maracas to my TV.

I have the same problem. I'm very disappointed. I believe that's false advertising because I have seen it work in 2 dell venue 8 pro commercials.

Same result here (it connects and can Extend but can't Duplicate).  Also it's annoying that the screen orientation of the Venue 8 Pro itself is forced into Portrait mode when "projecting."  This seems to be due to "auto-rotation" being locked when extending the display, and its default orientation is portrait instead of landscape.  I'm kind of curious is that might also be the reason for not being able to Mirror the display.  :S

Same here.  I can duplicate, but it locks at 800x600 in the middle of the screen.  There's no way to change the orientation... really frustrating.  Any word from Dell?  Miracast is totally useless in this state...