The +7 mana and +300 ldsp are not that useful at all, both not high enough to make a real difference (+1 Level and you get +250 ldsp as an example). +2 ATK and DEF is good but the following is what I have used.
For my Magician - Dragon Cloak:
+15% Defense
+15% for Attack Magic
I used it all the time till the end. 15% more DMG with Magic, woohoo. ^^
For Dwarfs - Dwarf (Steam) Armor:
+30% Attack
+30% Defense
But only effective with Dwarfs and -1 Tempo. But +30% more DMG always with all Dwarfs, unbelievable. It seems dwarfs have the most best items in the game, there are a couple of good combinations to strengthen a dwarf army.
Or from the Assassin Set, the Shadow Cloak:
Always -10% and at night -30% ATK from monsters, equal which one you fight. ^^
Or last but not least, Metamorphic Axel (number 7) with 2000 leadership. Can be placed at any slot.
Later I made my own Dragon King Set, which need all 8 item slots for a complete set. Because there are just a few positive items for dragons, I made my own. They're are a bit overpowered, but I was done with the game anyway. ^^ Was fun to make them with icons, info text etc. and get a full dragon army with every dragon. Yes they are imba now, but it was fun. Here's a screenshot of the icons I used:
I can upload it, if anybody wants them. But they are in German and, as I said, overpowered and only useful in combination with dragons. Includes the ger_items.lng (info & hint), items.txt (the actual items) and 8 PNGs (icons), so for English, someone need to translate them. Equal if they get translated, they should work with any version, but the items.txt will be overwritten.
But if you want +2 ATK and DEF so badly, stay at the Cloak of the Dark Lord. I try to get all critical chance I can find through items and push my magic, done. Compared to critical hits, those +2 ATK are a joke. But there is no critical in armors as far as I can see, so damage reduction and dealing more damage (with magic) is my way.