I have ridden and compared the Fuels to the GTO's. It sounds to me though like you have prety much read what i have said about them...which is good, so I wont have to repeat it. I'll re-cap though....
I personally feel like the GTO is more user friendly in higher and gusty winds than a Fuel...this is especially important to newer riders who don't have much time in higher winds.
I think the GTO is a better kite for a beginner than is the Fuel too, again because it is lower AR, it's easier to relaunch and more user friendly. They also aren't quite as fast as the 2003 Fuels.
If you are not a beginner, you prolly will be fine on an all Fuel quiver. As stated above, I am sure you would get used to it.
I find myself reaching for my GTO's in higher winds as much as the Fuels. It really depends on my mood and how I feel like riding this day.
A 9m GTO doesn't produce as much power as does a 9m Fuel. So...if I were going to replace a 2003 9m Fuel with a GTO, I'd prolly replace it with an 11m GTO.
The GTO is a 4 line kite, convertible to 2 lines....which can be nice to have around in the future when and if you decide that you'd like to try a 2 liner. Also, I personally feel like 4 line kites that are conertible to 2 liners are better performing kites in both 2 and 4 line mode than a 2 line kite that is convertible to 4...but I am only speaking from past experiences with 2 liners convertible to 4...and they weren't exactly modern 2 liners...so I dunno about todays 2 liner that convert to 4..they may be great kites.
I have probably more kites than any one man needs. If this weren't the case, and I had to pick a 3 kite quiver to purchase, I think I would probably go with an all Fuel quiver and detune the 9 as Wacker recommends. Don't interpret this as me not liking my GTO's, it's more of having an all matching quiver if I had to have just 2 or 3 kites.
The BEST thing that you could do, and what you SHOULD do if you can, is to try before you buy. I know this may not be an option for everyone, but for those that can, this is best. If you have flown the Fuels and you like them, then you already know that you cant be doing wrong by buying a Fuel quiver. But if you buy a GTO looking for a Fuels performance, you will prolly be let down just a bit. I mean, they do fine, they just are pretty different from the Fuels.
Hope this helps. I'll try to answer for you any specific question that you may have if you have anymore. Also, feel free to email me directly for SS information and literature if you'd like.