I've used the following tires on my Flux, each with their own pluses and minuses
Stock HPI GT2 tires
Pluses: Decent looks, traction and performance over all
Minuses: Chrome rims sucks, chrome falls off. GT2 lack tread for major dirt biting
Proline Badlands with Proline LRP Velocity Rims
Pluses: Major dirt traction, looked great. Never ballooned
Minuses: Couldn't run badlands on concrete with out shredding them, oversized sized rim gave no shock absorption and made truck slide alot, especially on firm dirt
HPI GT-S with Axial retro rims
Pluses: Great jump shock absorption. Large tread and soft rubber bite well into the dirt. Trucks bounces during crashes. Ability crawl over anything and looks completely kick ass
Minuses: Heavy, tires roll on edges, balloon easily. Axial rims stripped easily, paint easily flakes off.
Proline MT Mashers with HPI Dish Rims
Pluses: Proline tire foams rule. HPI dish rims look nice and cheap
Minuses: I hated the way they looked on the truck so much, I didn't bother to run them even once. I immediately sold them.
And coming soon, HPI GT-S with HPI Dish Rims.