I have both, an e30 and a e36 328i. I find the e36 a much better handling car. that being said my e36 is mint and the e30 is still a work in progress. but eventually i will be swapping a m52 and drive train into the e30 and doing a full coilover kit. then i guess it will be comparable.
but for the price of the swap and suspension, you can get a e36 and your off to the races with out much work.