I've been bitten by a black widow on the finger. It was in my sink. I picked up some plates and it grabbed on. I thought it was a June bug at first, then I had a sharp pain that ran up my arm. I took the widow with me to the ER. Not a fun trip.
My mother had a big hole/indented place in her calf, where a brown recluse got her.
Of the two I'd rather be bitten by the black widow. At least you know immediately when one of those bite you, so you can get treatment right away.
I've known two people that died from untreated brown recluse bites. Both were young mothers. It was very sad.