I started out using both pick and fingers a long, long time ago, but I found that for some reason picks were like biros and were never around when I needed them - I'd buy dozens, put them in an old tobacco tin, put them in my gig bag, get to the gig and they would have mysteriously disappeared...well not exactly, but I'd lose them pretty quickly.
So, I started playing fingerstyle because I figured that barring an unfortunate incident with a circular saw I was unlikely to forget to pack my fingers. I quickly became an exclusive finger style player and that remains to this day, some forty years later. I've worked out ways of making my fingers sound almost pick like, including hitting strings hard enough to clang the frets or holding an imaginary pick between my thumb and forefinger and using my fingernail as a faux pick. It sort of works, but not 100%, and here's the thing...although I'm exclusively a finger style player, I find that most of my favourite bass tones come from pick players, so I am forcing myself back into pick playing.
It feels very alien, as if I'm hitting the strings with a plank - with very little feel or sensitivity. It either hurts because I'm gripping the pick too tight and my thumb goes for the burn, or the pick is flying across the room because I'm not holding it tight enough. If I didn't know any different I'd have given up by now and stayed with my fingerstyle, but I'm not too old to remember the times when I played with a pick and I know it is possible to play aggressively when required, but also with finesse and caress the strings when needed as well. So it's on with the pick practise, without forgetting my fingerstyle chops.