Man, that's a tough question. I own both, but luckily we start 3 DBs
. I think Landry is the safer pick as he has proven before that he's capable of solid fantasy production and I see them both having the same upside. So I would go with Landry if I HAD to choose.
It's always hard to pass up a WLB that qualifies at DE. As long as he's starting, Groves should produce consistent numbers week in and week out, which is always hard to find at the DL position. I'd do Groves in tackle-heavy, Biermann is big-play.