I got the HR44-500. It was manufactured in May.
The activation process was a bit of a mess. They obviously had to remove the clients first from the HR34, and then remove the HR34. Since that was the only receiver on my account, it pretty much cancelled out all of my programming and options. The CSR then added the HR44 and the clients. Finally, I got her to add back the programming and Genie-Go, etc. This is where we ran into a problem though. She could not activate the Whole Home DVR functionality. (says not Activated). After waiting on hold for 20 minutes so she could get a programming supervisor to look at it, she came back and said it is a "known" issue and opened up a ticket. I think this might have been because she added the clients first before activating the feature. Anyway, I can still watch TV with the clients, I just can't use the DVR functionality. Hopefully this gets resolved soon. OH, I also had to tell her to order me a box to send the old receiver back which she did.
I asked her if all of my "credits" were still on the account and she said she added those back i.e. $10 off a month for HD, and $10 off a month for Showtime/HBO. I will have to verify that again though.
Overall, definitely worth the switch out even if it took about an hour total on the call.