I've planted both of them last year. CS is supposed to work better in our zone, but BI is more blue. So I decided to plant both varieties and hope for the best. CS should grow really fast when established. Here are date from the site I bought my BI:

Cupressus Arizonica 'Blue Ice'
Height: 30-50 ft
Spread: 15-20 ft
Growth Rate: Moderate to fast ( 10"-18" avg per year )

Cupressus Arizonica 'Carolina Sapphire'
Height : 40-60 ft
Spread : 20-25 ft
Growth Rate: Moderate to fast ( 12"-18" avg per year )

Thanks so much for the reply! Can you tell me how much growth they have put on in your garden since last year when you planted them?

Also, how tall were they when you planted them? And would you mind sharing your source where you bought them?

Thanks again!

As far as I know, they take a year or two (depending on size) to establish before they will start to grow. So my plants are approximately the same size I bought them last fall.
I bought CS at Home Depot for about $25-$30. It was about 3' tall and quite lush.
I am a little cautious to give information about online vendors on this forum because I was blamed in advertising once. So here is a disclaimer: I am not affiliated with this company! I found it by someone's recommendation on the Tree forum.
I bought BI from Evergreen Nursery. Perfect feedback on Garden Watchdog. I ordered their size 2 plants. They were 24-30" tall, but very skinny one-two stems babies. I would not buy a CS from them because it is widely available locally.
Good luck!

Thanks so much!
I am going to have to go to some nurseries to see the color difference between the two.