I own both and decided to use Substance Painter and keep Suite 2 only for some exceptional assets.
Substance painter is better in my opinion because:
It’s standalone software
Is stable all the way, no crashes like in suite 2
Has Iray
Bakes really neat maps
Mask generators work in real time, unlike suite 2
Managing and grouping layers is too easy and does not break anything
Once you learn it it’s VERY fast to work with.
It’s more consistent with UE4
You can customize the viewport all the way and use custom HDRi. You still can’t import custom HDRi in suite 2 which is really funny because then you don’t know how the asset looks in game engine.
Has a lot of cool little features like Lazy Mouse, particle brushes, Substance Share etc.
…
But still, you might just like Suite 2 more like many others so it’s totally up to you and not what we say really.