What sort of paintball are you looking to play? All 3 are upmarket, solid markers, it just depends on what you're looking for in terms of style and features.
Who am I kidding.....buy a Planet marker and never look back
Ego11 if you're playing in the woods where a little more air efficiency will help, or either the GEO/EGO if this doesn't matter as much to you or if you're playing sup'air. Might be better to get to a walkon day or training day at say CPPS/Bricket wood and ask a few people if you can try their markers out for a game. Most people are happy help and at least then you'll get a feel of things before you buy.
Some people say that an EGO will shoot differently to a GEO in terms of the balls flight path. This is a complete fallacy.....when clamped up, side by side, shooting the same paint, they shoot exactly the same. They will feel a little different to shoot but see what suits you best and take it from there.