1st Htpc. Please help.

The standard HDHomerun works fine with linux. I don't have the prime, so I can't comment. There some things that the prime is allowed to do on windows that it is not allowed to do on Linux.

Assuming you are planning to use MythTV, consider using more than one physical disk drive in your system, and keep the database on a separate spindle from the recordings. Database accesses can swamp the drive to the point that data is lost on the recordings.

My recommendation for mythbuntu is this.

• Small SSD for OS and /home suggest 64G
• Large disk designed for low power. i.e. 5400 rpm is fine. It's also quiet. suggest 2T
• You can put the DB and MythTV Storage on the same drive, However use different file systems. They do not need to be separate drives.
• I would handle it this way. Create a 30 G on the large disk or so partition and use it for /var. This will put all your constantly changing files onto the mechanical drive and not on the SSD. You might consider formatting it as reiserfs
• Use a symbolic link(s) to put the mysql DB on /var
• Create a large XFS partition for all the video directories. The MythTV wiki will give the details of that.
• I've been using this configuration with no issues at all. My system has 6 physical tuners and 3 frontends and there is no trouble with disk IO

Put the data base on a separate spindle, not just a separate partition. Separate spindles can be accessed in parallel. Writing to one will not prevent access to the other. The problem I encountered was that the database was thrashing the disk so much with small reads & writes that it held off writing the video stream so long (minutes) that the buffer overflowed and data was lost.
Putting the database on a separate partition of the same disk is worse than on the same partition as the heads are forced to move to a different radius for the different partitions, and moving the head takes time. If you plan to put the database on the same disk as the recordings, put them both on the same partition.

There was a bug in mythfilldatabase which was causing the thrashing. It's been fixed and/or there is an option to put the temporary files for it in ram.