I would pick the SWR. You dont have to use the Hartke 115. I would keep it for other gigs, or sell it. As 410 vs 410 the Mark Bass and SWR are pretty close. The BL is rated for 600W rms vs 400W rms of the SWR, but since you are using the same head with each, it is not much of an argument. Both cabs will take the power of your head depending on what impedence they are.
The biggest difference is tuning. The BL104 is rated with a lowend range of 45 hz, but is that -3db, -6db, or -10db? The SWR is rated at -3db @ 50hz. That is a pretty good, usable tuning. The slot port of the SWR is also less likely to "chuff" as the rear circle ports of the BL.
The speakers in the SWR are eminence, so a repmacement will be easily sourced should one fail. Not to mention, I think the SWR will just plain sound better.
Zon Legacy Elite 6, Aguilar DB680/DB728, Mesa Powerhouse 112.