pulltaber said:
I am sure you will get the same unbiased opinions on this forum as you would get by asking the same question on the AT forum.
I had the AT-pro for about 2 years,it started to leak after about 4 hours,sent it back to Garrett worked ok for about 6 months started
leaking again sent it back they fixed it ,then got to the point it would not GB sent it back they fixed it.....
I did not like how it felt in the water with the stock coil,it was like pushing a 2x6 board,I did not like the audio
I did find a lot of gold with it had good depth but it was not for me so I went back to a Tiger and have not regretted it.
But that is why they make so many metal detectors some like one thing some like some thing else.If you do get an AT good luck
My experiences exactly minus the problems you have had unless mine is actually showing symptoms of something going haywire.
I like the description of pushing a 2x6 board through the water; it's more like pushing a 2x2 through the water with the Tiger Shark. Something I want to stress though is if you get over waist deep, as in the water where both control boxes are submerged. They both become harder to swing or "push" through the water because of the extra drag of the control boxes. The difference is the Tiger Shark want to sink or stay down on the bottom where it should be because of extra weight. The AT Pro, I felt like I was pushing it down; I felt this more while I was holding down the pinpoint button to pin point using that feature. I also could not help myself but I kept wanting to pick the AT Pro up to see where it was pin pointing using the strength bar as well as look at the numerical read out causing me some frustration. That, on top on the tendency to want to float a little bit, I just stayed in the area where the control box stayed above the water level or just enough to read the face. I know many push the AT Pro as a light machine as a great feature and reason to buy and this is true if you are on land hunting parks or whatnot. However, if you are primarily in the water then lightweight is not your friend and actually makes you work harder. This goes the same for the Tiger Shark in reverse. It's heavier weight allows better control in the water but on land it's not a credit. The simplicity also keeps me from trying to look at a screen or pin point meter so that's a plus when I'm well over my waist in water. I don't mean to sound anti-AT Pro and I'm not, just pointing out some honest disadvantages since I have used it. I originally wanted a flexible machine and have found that in the AT Pro but now if I could have two detectors then I would leave the AT Pro on land and get another Tiger Shark. Both are excellent detectors and don't want to steer you away from one or the other. If I were you and did now know better, I would see which advice and information was matching up with the majority of users from both detectors and make my decision based upon what your primary use would be.
AT Pro advantages:
Land and shallow water use capabilities
3 tones
depth reading
pin point
light weight
Numerical target indicator
Notching
Decent depth on air tests if that's your thing
Disadvantages:
Only waterproof to 10' so no diving
hard to swing in the water
slightly buoyant (floating feel)
2 yr warranty
*per my experience so far, some falsing or picking up of mineralization in my local lake. Probably an isolated event due to some mineralization or something wrong with my particular unit.
Land rating: (0-10) 9
Water rating: 5
Tiger Shark Advantages:
easier to swing through the water
quieter running-less falsing
does not feel like ti wants to float-easier to control in the water
simple beep and dig depending on discrimination level.
200ft depth rating
lifetime warranty
Disadvantages:
Heavy on land
single tone
no pin point button
no numerical target read out
controls such as volume & sensitivity on inside of control box
Does not air test well, but ground performance is much better.
Land use rating (0-10) 4
Water use rating: 10 (freshwater)
There are more pro's and con's that can be mentioned and what is an advantage in my opinion may be a disadvantage in someone elses. Sorry for the long post, hope it helps you out though and you cannot go wrong with either one depending on your primary use and what you will let "slide by" in features and/or performance.
Habanero,that's the way it will sound when they start to leak .doses is do it all the time or just in the water? If you shake it and it falses then it is the coil, if it just doses it in the water it has leak,if it is ground mineralization,try to gb at waters edge and see if it falses.Next time you go to the lake try this stand it with coil up for a few days any water will show up between face plate and led screen. 
Let's hope not anway; I have been watching to see if the face shows signs of fogging up or not. Nothing so far but that does not mean there isn't a leak. By the way, it only does it in the water and yes if I'm in the water or on land and shake it, it does false but that could be the coil wire slapping the pole as it's only wound around but not taped or velcroed down.