The classic combo bluesbreaker+screamer with great mods.
The BB side has internal switches to change the clipping options (hard, soft, none or both). It has 3 very important thing to me:
1) It's very transparent
2) Cleans up really well when rolling down the volume on the guitar - I use it has a always on pedal rolling down the volume to get my clean tones
3) Reacts really well to your picking dynamics
The Screamer side also has internal switches to had bass.
This side really works well with the BB because it makes everything more mid-ranged and compressed for that "lead sound" sustain that will cut through everything.
Another cool thing about the ToxicT is how it stacks with other pedals.
I've been using the Blue Soul (Loco Pedals) has a germanium boost stacking with the BB side and works amazing.
Finally, for the price, it's very hard to beat, considering it competes with pedals that cost ~€150 euros more, like the Double Barrel or the Dualist.