I may get down-modded for this, but I suggest not releasing it given the scenario you described. I love open source, but most open source contributions are made for joy of creation, pride, fame, sometimes naivete (by assuming you'll get the benefits described) and finally, money. Many projects are created because they're ancillary to some business need--like SUN paying Charles Nutter to work on Jruby. These motives don't really apply to your case, and the benefits you list don't materialize for most projects. It costs you time to open source things properly and limits your options. Rightly or wrongly, some companies will be reluctant to buy you with your code released.

Statistically, most open source projects do not gain traction, significant users, free features, or free QA. They sit there on SourceForge, unloved. I wish I had a citation here. Try browsing SourceForge projects. Publicity-wise, consider how many you've heard of. It seems likely you'll get little in return for open sourcing. It's like a dance, and there's a decent chance that Baby will be put in a corner.