Is newer really that much better?

I'm riding an "old" bike 74' TS185, very modified. I need a real bike. There is an 86' KDX for sale in my area. Just so you know I ride with my bros. and nephew, 02' XR250 and 02' XR100. To me this is fairly new being an 86'. My friends tell me to hold out for a newer 90's model because the price diff. is small and the gains in amount of bike are big. I want value, but would also like to increase my skill level and have a bike that makes me smile. Price is an issue (I ride street bikes also, and they seem to absorb big chunks of cash!).:) I need some straight answers, is the 86' too old to compete with the newer models, not considering riders' skill?

NADA suggested price is approx. $400.00, but they (sellers) are asking $1000.00 OBO. I've talked to alot of people about this and I think it may be worth waiting for a newer bike to appear in the classifieds. I appreciate the older models very much, but the aftermarket parts seem to be more oriented to the newer bikes (of course). I'd like to stay under $1500.00, but you know how limits go? The weather is still nasty in ID, although I've been riding anyway, so I have some time to shop. I apprec. the input!!