The HD Homerun makes sense to me as an Ethernet device that can be shared. If not sharing, dedicating to one PC, I, personally, would prefer the in-PC PCI/e card, or the external USB.
However, I don't have room on the inside of my server for two dual-tuner cards, as I already need (2) Firewire cards for direct-STB recording. Also, I do plan to make a minimal recording DVR HTPC mini-ITX, and this would be problematic.
I have a small 4-way antenna splitter with four USB tuners (Hauppauge 950's) directly mounted right on splitter....very small/very cool. I have very short usb cables that feed a small usb hub (if you don't have four ports on your HTPC).
Works great.....I can record over these four OTA's plus three firewire STB channels simultaneously.
Think only downside is cost. HD Homerun at $69 is incredible. The Hauppauge USB's are a bit pricey now....I bought them new off eBay for about $55 each, and today these are a bit more expensive. There are others that are cheaper. With the HD Homerun, if you cannot get to an Ethernet switch, and need to buy one, the economics may change.
I struggle to believe that the HD Homerun connected to the same Switch as the "reading" HTPC could create any network problems. Traffic should be routed between the HTPC and HD Homerun across the Switch backplane...port to port and not affect anything else on that switch or on your home network.
Also, as far as quality of "picture," remember that this is digital. All these solutions are transferring data. Either you have a strong enough signal to lock on without drop-outs(and don't have excessive mutlipath), or you don't. There are not shades of grey for picture quality.....so again, I question the Amazon reports on the HDHRhttp://www.amazon.com/Hauppauge-1120...220107&sr=1-71