MAB and BP Damage are multiplicative so it's pretty easy to figure out which will benefit you more. Also keep in mind that Hagondes Sabots can be augmented with even more Pet:MAB (up to +25 additional for +50 total).
Here's an example of some math for magic BPs:
Avatars have 40 MAB native, and 0% BP damage. So let's say you use Eminent Pole, Eidolon Pendant, Bokwus Circlet, Caller's Sash, and Convoker's Doublet, just for a simple scenario, and you're trying to decide which boots to use. Well it should be pretty obvious Hagondes with up to 50 MAB will beat the Convoker's Pigaches, but here's the math anyway. Your boost without boots will be: MAB+170 and BP Damage +11%, giving a total boost of (1+1.7)*(1+0.11) = 2.997. So with that setup alone your magic BPs will do 3 times their normal damage. Now the simple question is whether 5% BP damage beats 25 (or 50) MAB. Let's assume you don't have augment yet so 25 MAB. The MAB will give you: (1+1.95)*(1+0.11) = 3.2745. The BP Damage will give you: (1+1.7)*(1+0.17) = 3.159. So even without any augment at all, Hagondes Sabots win.
Remember of course that's only for magic BPs. Convoker's Pigaches are still awesome for physical BPs. Flaming Crush gets a bit more tricky but suffice to say Hagondes Sabots wins for that as well.
____________________________Pergatory (Asura, Kupo LS) WHM99 ~ SMN99 ~ DRK99 "If you want to know me, look inside your heart." -Lao Tzu