Realistic Performance Measures of "Modern" PowerVr/Mali GPUs on Android?

[Furby]

So, the talk lately of which Android GPUs are best for PPSSPP made we curious just how bad PowerVR/Mali processors really are.

I'm curious because my two devices, a Droid Bionic and a Nexus 10, use a powervr and Mali processor, yet run games very well given their specs (My bionic does 20-40 in game (Pretty much no matter the game), and the Nexus does 30-50 in more demanding games (With the less demanding ones being upper 50's or solid 60)).

To put it into perspective of what I'm trying to get at, I'm looking at getting a Galaxy S4 (The Quad Core Version with the Snapdragon 600 @1.9 GHZ) in the future, since the Note 3 probably won't be available by the time my current contract expires. I'm not looking to pull something like Tekken 6, Soul Calibur, or other games of that caliber on it, but I am looking at playing games like Legend of Heroes: Trails in the Sky, Class of Heroes, other games with 3D Environments but little 3D interaction.

I'm wondering if those sorts of games will pull off high or perfect speed on the Galaxy S4. I'm aware that expecting more demanding games to run at max is ludicrous, but I'm wondering if a GS4 couldn't pull those off.

TL;DR: Just how bad is the powervr/Mali for PPSSPP use, anyway?