I started with Umami, mostly because I haven't used the app for awhile and was looking for improvements. I still like the interface, relatively decent ACR (took 10-15 seconds, struggled at first), and think it has a good balance of both Stimulating and Social features (no Simple, very little Seamless, and no Discovery). Apart from crashing 3 or 4 times, the app did well on what I was expecting in the Stimulating and Social elements. One important thing to note: I am watching a 1-week old show and the ACR works find (except in commercials). It also delivers the tweets based on the show timecodes--so no spoliers! Even though I must be a small minority watching the show a week late, there were tweets which I know had been shared a week ago as other apps (as I jumped around) had them their with their real world time code delivery (date and time that is).
I quickly tried IntoNow (since the recent feature improvements are enticing). I do like their Twitter integration and the ACR worked well, but you can see here that it is real-world timed (meaning spoliers). I swapped to Yap.tv--no ACR (you choose the show), but good social implementation--except all real-world timed, so again spoilers.
No images for TVplus (current favorite list). It did not pick up the ACR and you can't really "tune" the app without it (unfortunately). But ConnecTV did work. Recognized the right episode, but starting showing those sort of random facts that appear to be synchronized with the content but aren't. You noticed this when they start repeating.
Summary: I think Umami did a good job of managing a DVR'd experience. If you think there are other apps that perform similarly (recognizing what you are watching and timing the updates of Tweets, relevant content to the current episode you are watching), please let me know. If you believe the majority of consumers watch time-shifted content, this is a must for them (though clearly the networks want to push all of us to watch live).