I rate that a 16. A Verdungos I rate 21 - 28 depending on stats so it's a good belt for those of us who can't afford a Verdungo's.
That being said, I don't craft blood belts. It is not one of the best formulas, and IMHO the pruby could be better used on ring/amulet/glove/boot/Beserker axe.
Note: I give items a linear value. It gives me a quick way to decide whether to keep rares/uniques I find. The value is the equivalent of sc (small charms) I would need to achieve the same stats, and based on the usefulness and availability of that stat too. For stats not on charms, I derive the value from other items, eg. 1 socket = 4sc im armour, or 6sc in shield or weapon.
I value for each character class, and highest of those is the item value. So the above belt (for baba) is roughly :
10% chance to cast lvl 3 nova 0
24% fast hit recovery 4
3% blood leech 3
10% open wounds 6
44 life 3
29 to max stamina 0
While Verdungo's :
Verdungo's Hearty Cord
Defense: 125-158 (Defense: 58-65) 1
Required Level: 63
Required Strength: 106
+90-140% Enhanced Defense (varies)
10% Faster Hit Recovery 2
+30-40 To Vitality (varies) 6-8
Replenish Life +10-13 (varies) 2
+100-120 Maximum Stamina (varies) 0
Damage Reduced By 10-15% (varies) 10-15
Valuation for some stats such as open wounds is not linear, so 10%OW = 6sc, 25%OW=8sc, since OW is triggers a timer.
You can also factor in item requirements, so a spear for a baba I value dex requirement as 10Dx = -1sc. (5St/Vi=1sc so 10Dx=2sc but 10 Dx also gives 50 AR (attackrating) = 1sc)
Note this also lets you value skill levels, making it easier to decide which skill to raise.
I also find the valuation useful in optimising equipment -> I try to use the highest total valuation with the combination that also gives me the stats I need.
I'll bet you could lump in some linear programming from applied mathematics if you were serious about it.