95 vs 96-98 vs 99

Does anyone know the main differences between these Tahoe years? I am looking to buy a Tahoe that I will keep for many many years to come and I want to make sure that I buy the best one possible. I got a hell of a deal on a 95 Tahoe with 135K on it and I am debating if I should put my money into this one or if it would be better to wait and try and find a new year. I a pretty sure the newer years have the vortex but I am sure what the main advantages are. I am also curious of the differences between the 98 vs 99.
Thanks for any advice and comments.