I've experienced both of these cars. Had a Soop N/A Manual for about 8 months but eventualy the lack of power drove me mad!!! So I sold up and now I have a R33 GTS-T.
Firstly, the insurance didn't budge (maybe +/- £20)
Secondly, until you get into a Skyline you'll never really appreciate the build quality of the Supra.
Finally, it's until you own a GTS-T for a while you'll never really appreciate the reliability of the Supra.
Yes GTS-T's are much quicker without a doubt but in terms of build quality (both structural and mechanical), looks and presence I truly believe the Supra wins hand down!
That is why I am missing mine so much:(