My own experiments this evening unfortunately confirm wreelsw's experience. X2 will definitely NOT capture from a Digital 8 playing an analogue tape and connected via Firewire. Exactly the same experience as with VS11+/11.5+ namely, apparent capture for a few seconds, but then an error message saying capturing failed and the file would be deleted. I tried a few times, with both DV as the capture format, and also trying mpeg. Neither worked. Sad. But I will, as noted, continue using WinDV for such captures so that's not a deal killer for me.
However, my further experiments did NOT confirm Black Lab's regarding what I assume he means as digital captures. Using my Digital 8 with a digital tape, or my Canon mv930 SD DV camera, or my Canon HV20 capturing to HDV/mpeg-2, all via Firewire, the capture was smooth as silk, as was playback of the captured video. And all included audio (to take account of another user who has been having trouble hearing audio during capture, if I recall correctly, using VS10).
I might also note here that I have found X2 to be much faster at just about everything, than VS11.5+, including start-up, which only takes about 4 seconds overall, whereas I found VS11+/VS11.5+ taking about 12 - 15 seconds overall.
With high definition files, the extra speed is particularly noticeable, and especially with AVCHD. In VS11.5+, if I even clicked on an AVCHD thumbnail in the library pane, it would take around 10 seconds for the file to become 'active', and then a few more seconds when I tried to drag and drop it in the timeline. And remember, I have a Quad... With X2, both actions are almost instantaneous ... well, perhaps about 2 seconds.
As I reported in another thread, playback of AVCHD from a Panasonic SD9 camera is half and half. In VS11.5+, it would play for a few to many seconds, but invariably cut out, sometimes even crashing the program. Now there are no crashes, and the SD9 video will play absolutely smoothly in Clip mode but erratically in Project mode, but at least it will now play.
I also joined a few SD9 AVCHD clips together with transitions and rendered using the 'same as first clip' command, and that worked just fine and again was quick. I didn't use SmartProxy. The resulting file has the same properties as the original but plays smoothly -- though I have to say that it is still a bit jerky in Project playback...
Regarding one of my other complaints about VS11.5+, I now find I can use Make Movie Template Manager to make a template for HDV format. No problems. You use the mpeg basic template but now it allows variations of the bitrate up to 25 mbps and frame sizes up to 1920 x 1080 (which is a little strange since the maximum size of HDV is 1440 x 1080).
But sadly this is not apparently possible still with AVCHD video -- at least in my experiments to date. I will look forward to others proving me wrong!!

And I hope to be, as I can think of no logical reason why Corel would not have allowed this for AVCHD when X2 has otherwise taken steps to make the program's performance with that format so much better in other respects!
Another positive, I got Canopus VideoFX transitions plug-in showing up -- and working fine -- in X2.

I will try tomorrow with my Adorage plug-in!...