I used to transpose everything, but then I'm not on the same page as the guitars when we discuss something regarding chords or morphing into other intros, etc. I mean, it's not rocket science but I finally have decided to drop tune even on the 5 string so that I don't have to change my bass patterns between where the BAND plays the song, and the recorded version I practice to at home. The bass-lines are played the same. We don't have our own recorded practice tracks, so I use MP3 i rip from Youtube, etc.If the rest of the band tunes to Eb (probably to give the singer a little more range) I would tune down also. For a few songs, transpose.
Side note: The 5 string messes with the guitarists heads because they can't look at my hands and know what note I'm playing. The B looks like their E string, and this caused a few arguments along the way even though I was in-tune with the chord. They thought it "looked" like the wrong note. And when I used to transpose 1/2 step down on top of that, their heads would explode. It was entertaining for a while, but I don't have time to practice 2 basslines for all the songs (standard and drop tuned) so I bailed-out and tune down with them. One of the guitarist's head is still spinning . . .
on riff oriented songs that use a lot of the open Eb. My only alt tuning basses are in drop D a fretted and fretless.