You're damn skippy sir. Seen many a brown relcuse and only one black widow in the wild. I know the recluse is potentially more damaging, but they never got the response from me the widow did. Not gonna lie, I backpeddled like a wuss and had my girlfriend kill it.
Black widows like to hide under rocks, plastic, and other things. They are mostly predictable. You can usually check for one before picking something up. They are also easier to spot, being so shiny, and larger, and distinctive.
Brown recluses infect buildings, cannot be poisoned by the usual means (because they don't clean their legs), can hibernate for weeks with no food or water, hide in clothes, and boxes, are difficult to spot, except when they run across your bedspread at night (if you are lucky) or your face at 2:00 A.M. (if not so lucky). Even if you vacate every week and gas bomb it for a month, you'll only kill the ones in the house. They'll migrate back in within a year or two.
My dad has been bitten by both (lucky I guess). A black widow bite, unless you are very young, old, or have a heart condition, you've got a good chance of surviving even without professional medical care. Like a rattlesnake, you'll be sick for days, and need to stay warm and fed, but you'll get better most likely. A brown recluse bite, unless you are very lucky or got a trace amount of venom or got professional care within the hour, you stand a good chance of needing months to fully heal. Untreated for just a little too long, you could easily lose a limb or worse.
If I built a fantasy monster on the black widow, and sent it after my players, they'd find it somewhat scary. Then they'd squash it or run and move on. If I sent the equivalent built on the brown recluse, half of them would probably leave the session. A "giant brown recluse" would make phase spiders seem tame.