I've used both loaders currently running on an egg.
Pros for halo
*It's a true force feed loader???? as if this really matters but hey
*Will feel very familiar to a revi user as the lid and profile are similar,
*Feed neck feels more substantial, altho it's not replaceable.
Negatives for halo
*RELIABILITY!!!!!!! i had several niggly problems with mine
*vision is impaired by the back of the loader (Bit slab sided in my opinion)
*HEAVY!
*Pain in the arse to clean
Egg Pros
* Cheap replaceable parts (feed neck is a bonus)
* Holds more paint
*Vision is better allowing for a tighter profile
Egg Cons
* it looks like an egg
*may off balance your marker
* a full loader will put a lotta leverage on the feedneck (may spin or fall off in frantic activity)
* Lid is curious design that takes a bit of getting used to, but does allow for fast fills while still firing.
* battery tray is toss!!!! tape it up or lose your batterys
All in tho i'd say get an egg- they're cheaper and spares are cheap too
A.B