seac sub asso 115 vs. cressi sub SL star 100

Hello to all you spearos accross the pond! Now that I'm home from Colchester, England, to my beautiful Southern California coast, my spearfishing days have resumed. Be that as it may, I must say that I've been recently very disappointed with the inaccuracy of my 120 cm Picasso Century Pacific. Having used a couple of pneumatic guns and band guns, it's become my firm belief that a pneumatic is generally easier to keep accurate out of the box - with band guns, you have band length to factor in, weight and ballasting, etc. All of this requires pool testing, and a pool I do not have.

So, to make a long story short, I'm in the market for an air gun. My old Cyrano is having problems, and I don't like the 7mm shafts that come with the gun (they bend too easy due to my spearing on the rocks), so I'm going to leave it alone for the time being rather than try and repair it and purchase a new shaft (a sweet gun, though). I definitely want to upgrade to the Mamba kit at some point. My question to all of you is this: would it be better to purchase an Asso 90 or 115, or a Cressi 100? I want the gun for "all around use", i.e. rocks, reefs, and open water.

Chief concerns include:

1. Overall power
2. Availability of quality replacement shafts
3. Durability/Reliability
4. Ease of transformation with Mamba kit

What I'm not concerned with:

1. Ease of loading

Thanks for any tips you guys might have in advance.

James