12 stamina and 1 Int isn't a serious consideration; 15 mana is nothing, and Stamina isn't worth it so long as you have enough. The choice comes down to how you can best gem them.
If you're matching sockets and trying to make them as equivalent as possible, the gemming is:
Sunblessed
22 heal
10 haste
11 heal/2 MP5
NJC
11 heal/4 spellcrit
11 heal/4 spellcrit
11 heal/2 MP5
The trade-off is then 4 MP5 and 26 spell crit against 24 haste. 4 MP5 isn't that big a difference when you already have 120-150 MP5 on your gear, so it's really down to what's worth more to you - 1.3% crit or 1.7% faster casting.
Alternately, you could jettison the idea of crit on the NJC entirely. Instead of the 11 heal/4 spellcrit gems you could use Spinels for a +22 heal increase over Sunblessed, or fill all three sockets with 11 heal/2 MP5 gems to make it a straight up contest of 24 haste vs 34 crit.
Looking at the two items as a Healadin with BS, I'd go with
[Sunblessed Breastplate] ... but I'd be thinking of
[Noble Judicator's Chestguard]. If I could muster around 25% Holy crit without Sunblessed, it wouldn't be a contest.