I too started with Airfix, great stuff. I lusted after the 1/24 Spitfire and got it one xmas. Marvellous. On occasions when I didn't get enough poscket money I would have to by Revell, but I was never happy.
I only once bought Tamiya, fantastic model Kettenkraftrad, 1/2 track motorcycle. Unfortunatley they were too expensive for me.
I also once bought a KeilKraft ME109, rubber band powered model. Balsa and tissue paper. I over doped the wings and they went banana shaped ::)
But that was many years ago.
Currently I like sail. I think the sight of canvas over water is very aesthetically pleasing. I also have acess to a small ornamental pond that is about 80m by 25m, with ducks and several hundred large gold fish, and thousands of minnows. Because the sail boat is pretty and quiet nobody has complained yet.
The pond is only small, but it is in a hollow, and is surrounded by tall buidings. This makes the wind challenging, as it can turn 180 degrees within a couple of meters. Some days it is possible to sail up one side of the lake with the wind behind you, and back down the other side of the lake with the wind behind you.
The pond is probably too small to have a lot of fun with many motorized models. Imagine a 12ft warship, I would need a tug to turn her about

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My first was a Victoria sail boat that was not expensive, to see if I enjoyed sailing. I love it.
I am now working on a Mary J Ward. This has been a challenge, as I am modifying it. I have given up trying to source stuff here in China, it is very frustrating. There is no poly urathane, no dowling, and not all standard tools are available.
Everything I buy in has a big postage charge. For example the inkjet decal paper someone introduced on another thread. cost 1.50 ish per sheet, postage about 7.00ish.
My next model will be a scratch build, probably the Higgins boat. I know I will be able to source most of the stuff here.