Id add some stuff having owned both for at least 6 years- E30 tax(obviously), all E36 front end benefits - 5 lug\wheel selection, plug and play steering racks, M3\vert underbrace, camber washers, easier to work on and generally far more part options available.
Rear end is easier to work on due to more space and the inner brake lines are way easier to change.
E30 benefits that i can think of - factory medium case diff and axle setups if you doing a engine swap\power upgrade. Some interior stuff is higher quality - door cards, headlining etc. Proper spare wheel. Old style sport seats and no airbags (preference). Possibility the having a stiffer body due to rear seat bulkhead.
Great engine which suits both chassis with a manual box. Always wanted to see it in a drag race - M44 vs M20B25, i reckon the M44 would do ok.