seacsub and tigullio are respectable brands: the products you mention are reliable and well built, but also nothing particularily special...
so what's best? I've tried many and I think it really depends on different hunting situations.
The expensive Mamba, with its revolutionary "dry" system (no water in the barrell, 40 meters per second shots), is absolutely the best pneugun in longer sizes for aspetto and open water.
BUT I wouldn't use it for cave hunting, absolutely not. You don't need so much power for shooting into rocky holes, where you can damage the shaft and crash the expensive mamba kit components.
Same as above for the beautiful Cyrano (and expensive too): 11mm barrell with conic shape gives good speed to 7mm shaft, and easier side movements too. But that's particularily useful for long size in open water shooting.
While IF you're looking for a short-medium size gun, for a mix of agguato and cave hunting, I still think that a omer tempest 70 is a good balance: solid, powerful, accurate (7mm shaft) reasonable in the price.
Finally, for CAVE ONLY, nothing matches the short older models with 8mm arrow such as mares mini- or medi-sten and sporasub rafal, very cheap, very solid and perfect for hard work in rocky holes.
more puzzled than before?