If you actually want to enjoy watching a recording remotely, then nomad is a great option, and to be honest, it's the only "real" option for DirecTV content.
Slingbox (I have two - one on each HR34) is nice for a quick check of a "live" sporting event or when you need to access an individual receiver for any other reason, but if you want to watch a recording just like you're sitting in the room with your DVR, then nomad is perfect.
It still needs a little work, like a native iPad version, but I've used it dozens of times, and it's a great experience.
Recently, I've also brought along the iPad HDMI adapter and an HDMI cable, I've been lucky that most of the hotel rooms have had HDMI capable TV's, and the picture quality is not bad even on a large HD set.
The routine is that a couple of days before I leave for a trip, I transcode 5-10 recordings, I download them to the iPad the morning I'm leaving or the night before, sometimes also to the laptop (it uses the same transcoded file for both), and then I have the iPad for the plane, and the iPad and laptop for the hotel room.
For my recent flights, I've also added GoGo inflight internet to allow for online access at 30,000 feet to eMail and the forums, while also watching a nomad recording or two, and it's transformed the flying experience from boring to very productive.
Good luck if you decide to purchase one, it's fairly inexpensive (one time charge - no recurring charge), it's easy to setup, and we're always here to help. Enjoy!