This is my analysis of Holy Panda vs Zealios V2.
Both switches are aiming towards a large and round tactile feel.
I personally felt that Zealios V2 is a more polished version of the concept, since Holy Panda was an “accident” while the Zealios V2 was actually a proof of concept brought to execution.
Zealios V2 proved to be superior than the Panda when it came to Tactility and Tactile Roundness. Panda housings are a good middle ground between Retooled MX Blue housings (Good for large and sharp tactility) and Zealio V2 housings (Good for large and round tactility) in this regard.
When it came to stems, there were trade-offs. Zealios V2 stems were more tactile while the Halo stems being more round and long drawn out.
I would recommend mixing parts accordingly to your liking. I would have to say, I am very impressed with Zealio V2.