The XRC 800 is a wonderful ski for an improving intermediate skier who aspires to carve and improve in the basic skiing fundamentals. It is Harald Harbs ski of choice for intermediate skiers, along with the Head Super Shape which is certainly less forgiving. The turn radius on this ski at 170 cm length is 13.3 m which makes it a just a little wider than most slalom skis. This ski will hold well in most hard conditions and can be taken into some powder, crud and chop and hold up acceptably.
Of the ones you mentioned, this would be my pick but I must admit that I really don't know the Blizzard ski.
The $425 price is good for a local shop. You can get them at Level Nine Sports for $309 with an LD 12 binding or $199 flat. I have done business with Level Nine and they are solid. For the extra $116 you get a local shop that you can bring the skis to in case you have a problem. Odds are you won't (level Nine will set your bindings and they are railflex bindings which are ultra easy to adjust) and if you do, it most likely won't cost you $116 (probably more like $30).
Here is the link in case you care:
http://levelninesports.com/head-2006-ixrc-railflex-skis-170cm-p-874.html