Josh,
There are several AZBox models out there and they all have their merits and their troubles. Personally, I like the Premium Plus, but I hate recommending any receiver. Everyone's taste and desire are different. Especially for the AZBox. It is a totally unique world for these receivers.
HDD for the AZBox... try to stay with a 5400 RPM drive and not go with the 7200 RPM models. The Samsung HD103SI HDD works great.
DVBS-T tuner... You will have to buy this separate and install it yourself. The Premium Plus is probably best suited for this option.
Blind Scan, 4:2:2, DVB-S2 are all there on the Premium Plus. AND you get WiFi and the front panel VFD display with this model. I think that these are options that you will desire highly.
A 1 TB HDD holds much more content than you realize. I have approximately 165 full length movies PLUS approximately 130 GB of recorded HD programs from satellite recordings stored on my HDD and it shows 78% full. This is like 350 - 380 hours of viewing, maybe more.
Before you decide on the AZBox, read the A-Z guide in the stickes. There is a section in there that includes Q&A sessions from real members here. That will help you learn about the box itself.
RADAR