I can round it of to....if you want a removable battery(very useful if device freezes and becomes unresponsive) and sd card slot then go with the Nokia.
if you want something with a larger battery better screen which is an LCD 2 with a huge ppi which I think has better energy consumption then Aoled displays, and gorilla glass II , then go with the HTC which has twice as much internal storage then the 820.
those are the only different advantages I could find but before saying that Nokia has pre installed some of its apps first check if HTC hasn't juiced the 8X with a little sense like functionality as well as HTC hubb. htc have also been in the Windows phone business longer, remember the HD 2 ?
these devices are so similar that its like asking which 2kilo gram rock will fall faster is one is painted green and the other yellow. its hard to answer.
The 8X has a bigger battery but its built in...how much storage do you need ?
I love using apps and as I know Windows apps consumes quite large amount of space so it might be possible that 16 GB of 8X might restrict my usability. Since there is no external storage support in 8X Lumia 820 seem to be a better option for me as of now Windows 8 allows you to store your apps on SD card.
Sure I will wait for some time so the price of these phones will fall and I can get it at bit lesser price.
Thanks for your continuous support KTW.