I switched from Dish to DTV earlier this year and haven't had any tuner conflicts. DTV is more accurate with its timing so I've found that I don't need to extend recordings or start early. This helps with the #of tuners needed as it cuts out overlaps.
I did opt for a HR 24 to complement the Genie but don't need it. We have all of our "important" stuff set to record on the Genie and use the HR 24 for stuff that doesn't really matter if it records or not.
One downside I've found with this setup is that you can only stream 1 recording at a time from the HR 24 at another location so keep that in mind.
Concerning the Hopper3, I've found the only feature I really miss is the Sports Bar mode. I would love to be able to put 4 NFL games on the screen at once but that would be having your cake and eating too.