I switched from a fascinate too a tbolt.
As far as the switch goes, my tbolt functions just as well, if not better, in a stock state than my rom'ed and rooted fascinate ever did.
4g is incredibly fast if you are in a 4g area.
I used to love the amoled screen, but found that I like regular LCD better. While the smiled has brightness, true blacks, and power consumption on its side, I did not realize how oversaturated the color palette is on amoled. The regular LCD is dimmer, but to me gives a much truer to life picture.
As far as jumping to a new phone, I say definitely jumps come September. Don't hesitate to try something other then Samsung. I think you will be pleased if you do.
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