On the subject of math...

AoS is interesting because it does not cap at 2+; you can have autohit/wound. So the math becomes interesting.

A unit which hits on 2 and wounds on 4 will (with a nominal 36 attacks) get 30 hits and 15 wounds. If you have the choice of a +1 to either hit or wound, the average results are;

+1 hit / 4+ wound = 36 hits, 18 wounds

2+ hit / 3+ wound = 30 hits, 20 wounds

Although it seems good to get the autohit, in this case the situation is very distinct.

Also, bear in mind that all bonuses and penalties both stack AND apply to the role, not target. So, if you stack bonuses to get an effective 0+ to hit 1) you are actually adding something to your roll (eg +2) rather than changing the target. So if you roll a 4 that is a six and will trigger special rules that need a six to activate. Also, 2) it may be worth getting stacked bonuses to give and effective 0+ or better to hit in order to increase the chances of triggering such rules and to counteract enemy minuses.