I have it and personally don't like useing it, doesn't go well weith my stealth based characters. And the only other types of characters I use are stealth/mage, pure mage, or a two handed Orc. Never really use sword and sheild types. Besides, it blocks magic, which is already easy to just dodge. Kinda just a fancy Drawven shield to me.
Somehow i got the Spellbreaker without doing the mission. i already had it by the time i did the mission. When i completed the mission, i didnt know what daedric artifact i was supposed to recieve, so i was upset when i didnt get anything. i later found out it wwas due to the fact that i already had the shield.
All I can say is this is the best sheild, if you have those special ward perks and the arrow perk because then all that can hit you are melee and the base defense is great so well, It makes it the best sheild. and get the deadly blow perk, and well, it's a weapon too! which makes it better than it already is.