This year I played all jazz at my Delta State University faculty recital. Program and some selected videos are below. I’m very much a part-time jazz player, so it was fun to spend the summer trying to get my chops in shape to play tunes in a variety of styles on a variety of instruments. ... 
Every so often I hear from people about what I call the E-flat contrabass clarinet (or “contrabass clarinet in E-flat), such as in my woodwind doubling in musicals list or in my woodwind methods book. Some prefer the term “contra-alto” or even “contralto,” but I find “contrabass” to be the most accurate and useful description ... 
Overall, I guess I lean toward the Hercules a little for bass clarinet, mostly because I could add, say, pegs for B-flat and E-flat clarinets and be ready for a utility clarinet gig. And I like the K&M slightly better for bassoon because its larger, softer cup makes a better target during a quick instrument switch. 
If you expect to play the clarinet decently well, you're going to have to do all the same things you did to play the saxophone decently well: obtain good quality equipment, seek out quality instruction, practice regularly and well, and listen to lots of fine playing. 
A new Internet friend shared this gem with me (click for slightly larger):