Hi Zach, glad you're getting out there and playing your upright.
Sometimes it's helpful to know what bass you are using, which strings and what kind of music too.
But for my pennies worth:-
I'm not an expert, and I'm not a sophisticated player, I just like a good old thump. I have a Schaller on 2 of my double basses and I love them and so do the acts I play for. Thomann do them new for just under £100 + pp They're not everyones cup of tea, but there you go mate.....
No feedback problems, but, for some, a piezo is the only way, I'll let the proper players talk about those.
[url="http://www.thomann.de/gb/schaller_kontrabasspickup.htm"]http://www.thomann.de/gb/schaller_kontrabasspickup.htm[/url]
John