I remember when the HR34 was introduced, people were going crazy trying to get one. There were almost hourly updates on availability.
Then the HR44 is announced, and the HR34 becomes a "POS."
The two units run the same software, have the same number of tuners and storage capacity. The major difference is that the HR44 has an outboard power supply and a smaller form factor. I can see little evidence that one model is more or less reliable than the other when running the same software release. While the HR44 is somewhat faster, I would hardly call the HR34 "slow" (it is comparable to our HR24s and H25s).
As to why only one Genie is allowed per account, I suspect it is more an issue with the current state of RVU client software (both the DirecTV clients and RVU capable TVs) than anything else.
Human nature, humans always want the latest and greatest toy for bragging rights, same thing will happen when and if a HR65 is announced