So here is the difference between DirecTV TiVo and Comcast DVR aside from the obvious point that Comcast DVR stinks in general. 

The difference is that with DirecTV Tivo once you pause a screen to freeze something worth looking at such as let's say Chuck Lorre's vanity cards at the end of Big Bang Theory or Two and a Half Men, it vaporizes in no time.  With Comcast, you are screwed.  It stays there like a stone wall put up by the DuPont's in the 1800's for little else reason other than to annoy others with their ability to do it.  There is no real thought behind it and therefore the lack of foresight means it will cause problems later. 

Sure I watch Big Bang Theory and Two and a Half Men, but I also watch the news and other important programs that require me to freeze or pause the screen.  Even my five year old needs that important feature, but when you get a green bar at the bottom of the screen that refuses to go away... well... that little five year old's feelings are crushed.  And do you really want to see five year old children abused in such a way? (I'm kidding of course)  I sure don't.  But who will hear this call to arms?  Who of us are men of action?  Will no one tell Comcast they have their head straight up their butt?  Doesn't anybody care about my children?

And then their are the other differences between DirecTV TiVo and Comcast DVR.  You can't control the fast forward speed with Comcast DVR while with DirecTV TiVo you can hit pause at triple speed, then hit play and go right from that point.  And of course it fast backs at double speed so you don't miss the beginning of the next segment after a commercial.  Unheard of and impossible with Comcast DVR.   Sure Comcast has four speed to DirecTV TiVo's three speed.  They are both the same in my opinion, you just get no control with Comcast DVR, so what use is four speed then?

Oh.. I could go on.  This is a tragedy... Why did I ever leave DirecTV TiVo?  I means... now I don't get to watch my Sunday Ticket Either.  I don't even want to go there.  The only benefit there is I'll be out more on Sunday's this fall.  ...Oh wait... I was anyway.  I recorded my games to watch at night when the boys went to sleep! 

Comcast is all excited to now offer dual recording DVR's.  I have one.  Blach!  DirecTV TiVo's have dual recievers that allow you to cache two channels at once where you can toggle back and forth between channels and rewind a half an hour into each one.  Live TV cache'd on two channels at once.  The closest the Comcast DVR comes is that you can record one channel and watch other channels at the same time.  For smart viewers, this far less quality by comparison.   If you want to toggle between channels with Comcast, the only work around is hit record on one channel and flip over to the other "so called" reciever to watch other channels.  This does not work well, I won't explain how lame it is.  

Comcast DVR has no jump points or markers to advance two either. You can either skip to the end (Live point) or jump back to the beginning of the cached broadcast.  Again, falling far short of the advantages DirecTV TiVo offers.

You can hack a TiVo easily and put a larger hard drive in it to record more shows.  Out of the box, the Comcast DVR records 60 percent less than a TiVo (I'm talking HD programming on both).

Comcast doesn't offer a season pass function.  Oh it has one but it doesn't have the umph of the TiVo season pass.  In short, it doesn't work well. I've missed shows and that is a sin. Some reviewers will say that they are close... But they are comparing the planned recording features only.  When operating in a live environment, TiVo rules, Comcast DVR falls short.

So now I get no Sunday Ticket and I can't read the last three line's of Chuck Lorre's Vanity Cards when they air!  Sure the Internet is our savior, I can look them at  Chuck Lorre's Official Vanity Card Archives.
AFTER the fact. 

I give a single nod to Comcast for Video on Demand (VOD).   My kids love it and yes.. my five year old knows how to use it.  But it took a lot more training that the super simply TiVO interface. 

The only real answer?  Comcast TiVo!  It could happen!