I'm making a pilgrimage to B&H in NYC tomorrow to buy a bunch of stuff which will include a BeachTek DXA-8. I'm looking forward to browsing the store.

But I'm still undecided between the AT3031 and the Octava cardiods. I want a stereo pair for live plays and musicals which will sometimes be miked by the house and sometimes not. When not setting up for my own stereo I want to use one the mics as a room mic while I take a line input for the other channel.

Based on some comments I've gotten here, I'm only half kidding when I say I wouldn't rule out getting one of each and forcing them into a stereo pair by tweaking levels.

But since I'll be at B&H where they have the AT but not the Oktava, I may succomb to the convenient resolution of getting the AT's

Any eleventh hour advice? Thanks.

I think I'd fall to the AT's. They are quieter, more sensitive and a little more convenient. The pad is a switch rather than a separate component and they also have a bass roll-off. The mic clip is more convenient, the windscreen is included. The AT's have less handling noise too, even without using the bass roll-off.
My Oktava has excellent sound, but for stage plays I think the 3031's are more useful, especially if you aren't specifically going to get the hyper capsule for the Oktava(s). They really do have a different character, that's why we end up with so many mics... They are both good sounding, just different. It's not a mistake to get either one.

Thanks Jay.

Is there any difference between using the pad on a mic versus attenuation further down the line?

I'd go for the AT as well. The build on AT stuff is really solid, it is pro quality gear.

If the attenuation is ahead of the mic preamp then that's actually more desireable.

Bryan is correct, an attenuator that goes between the mic capsule and the mic preamp (like the Oktava) can prevent the mic itself from overloading. I assume the AT switch works the same way, but you'd have to look at a schematic to know for sure. Once the mic overloads, then you can't fix that with attenuation placed downstream.
From a practical standpoint though, you'd have to be recording some really ear-splitting stuff to overload these mics and need the onboard attenuation. Generally it's the mic input of the recorder that's designed for an SM-58 that's at risk. In that case, the inline attenuation that goes between the mic and the input will work just fine.