The BDI21 is a clone of the Tech 21 - try it for the few dollars it costs & if you don't like it spend the lots of dollars for the non generic one.
I can't think of a rock song I truly love that has a 5 string bass playing on it. I do know a couple of songs I like at lots that have 8 & 12 string basses but hey're just octave fiddles of mud around the basic 4.
Hey, they have their fans & players who swear by them BUT...it always remains BUT doesn't it!
THe 5 string bass is the SUV/4WD of the bass world.
You've gotta have one, it's rugged, it goes off road, it'll save you when the apocalypse comes, it goes up to 11 etc. BUT, (there's that word again), it gets 99.9% of it's use doing the mundane things that 2WD/4 strings do & for that 0.1% you have to create the circumstance/excuse - UNLESS you're in a Death Metal band who'd have a stretch black Jeep because it matched their occult jewlery anyway. (sorry to all DM players/fans - I was lost for a conclusion to the analogy so whipped up that perposterous one to fill in the gap).