Hi Murat,
If you spend enough time reading this forum, there are a few threads which discussed guns in great details, it might help you. Surf around.
Of all the guns you listed I am only familiar with Riffe, but unfortunately I have not shot a Metal Tech before but a friend of mine has a Metal Tech #3, it is still a virgin so even him have not has the chance to shoot it. Damn its been a month already !!! However I can comment something about its construction because I study it thorougly. I do own two Riffes both are teak ones. Since I am impressed with a Metal Tech I ordered one MT #0, it was supposed to be in my hand last week but some shit happened to it...somewhere and I don't want to talk about it.
As our Sultan ( Icarus ) have explained on the better points of a Metal Tech #3, I would want to explain further. Your gun list number 2-5 is not exactly something you can compare to a Riffe because the concept of the design is different and so are the pricing. Riffe Metal Tech was actually introduced to allow cheaper retail price compared to the teak models ( The Riffe Competitor Series- Teak is not that expensive ). Since teak wood come from trees, prices should increase every year because there are less tree to chop. Metal Tech is made from aluminum, therefore it can be made for a decent price because mass production can help pricing down.
Jay Riffe is a perfectionist ( boy, I said this twice already ) and he is also a world-class hunter, everthing he design and manufacture has always been over built. Why, because he knows that you and I will one day want to put as much power as possible in our guns because we want to pursue bigger fish or want to shoot a stealthy fish from far away, this is part of a spearo routine "growing up".
In terms of construction all the other guns you mentioned are not worthy to compare to Riffe Metal Tech ( except Totemsub, cause I never seen one ). For those who has play enough with guns, we can tell a solid built from an average built. If a Metal Tech is a Mercedes 600, the rest is like say a Honda Accord. All serve the purpose as a speargun, you can hunt with them but the feel and built is different.
Jay Riffe built guns the opposite way to all European guns. Since JayRiffe and all of the previous and current world class hunters are mainly after the big tunas , his designs , especially the trigger and the muzzle design has been focused more for big fishes, meaning for big power. All of his guns uses the same trigger mechanism. All the small Riffe guns are just scales down Riffes. His pride and joy is the Island and the Inertia Blue Water.
European guns on the other hand was design initially for small fishes and later people demand more power and thus more bands are installed. Trigger mechanism is the heart of any speargun, it is also the most difficult piece of engineering in a gun, I mean if you talk of something capable of 600 pounds or more of rubber pressure. If you look at how a trigger lock a shaft, you will know how critical a good design is.
I am not saying you can't shoot big fishes with a small 6.5mm shaft Euro gun, many people have had good success but do you know how close are the shots made, do you think there are such opportunity for every hunter, do you think we dive the same rich fish area ? A small 6.5mm shaft with a single flopper has very good penetration because it is thin and slimline. This is the only advantage I see of a Euro gun. Everything of it is small and thus very fast to swing in the water. If a 30kg fish always maintain 5 meter distance from your speartip, I bet you won't be able to nail any with Euro guns, unless some very rare model.
Simple obeservation should be made. The power source of all the speargun you mentioned is the rubber band. Therefore the more rubber the gun can take and of course its trigger too, the more power potential it has...simple. Unfortunately, not all guns are created equal in the trigger, muzzle and barrel strength area. Yes, there is a limit to what kind of power you can put on a gun before recoil and shaft whip come to play. For the Metal Tech #3 with 3/8 (9.5mm ) shaft, it can be powered all the way to 440 pounds of rubber pressure ( 5/8 x 4 bands ) if you get the new aluminum muzzle, a basic muzzle can handle 340 pounds or 4 x 9/16 rubbers. Anything above 340 pounds of rubber pressure, a two hand shot is a must...... for me. This is also the proper method of shooting a mid handle gun, regardless of power. The more hands u placed on the gun, the better the aim is.
If you are saying that you want to a gun that can grow with your needs, I think the Riffe Metal Tech is the only way to go if only one gun is the criteria. You can always go for Mt #2, instead of #3. Shorter swing faster. The Riffe Metal Tech will come with the enclosed track soon and I heard the enclosed track module can come as a kit, this mean 1 gun can be used with 2 enclosed track, one for 7mm shaft and the other for 8mm shaft..... as required. All you need is to buy extra enclosed tracks, buy the gun in the standard open track, buy 2 shafts, one of 7mm and one of 9.5mm. The 8mm comes as standard. There is no other gun I know of that can be this flexible.
As for your listed Euro guns, if it comes with 2 bands/rubber, that will be the way you are going to have it for the rest of its service life. Why, cause 2 bands of 16mm is about all the maximum power a 7mm shaft can handle.
Another simple point to observe is that, if something which retails supposedly "expensive" ( Riffe ) can sell so well, there is only one reason.... it is worth the money and it is a good product. Remember a speargun is not a fashion goods, quality and function is the selling point.
If I were to point out honestly, European make many fine cars , unlike many American brands but as for a speargun...... American Riffe is a good choice.
Don't worry I am a neutral person, not European not American.
Have Fun,
IYA
