When giving a bj, is it most enjoying when you have a flavored condom, or have no condom and let all his cum go in your mouth or let him cum on the bed or floor or whatever, or should I just spit it out?
You should swallow every last drop.
First of all, if you don't know the guy very well, use a condom. Second, whether you want to spit or swallow is up to you. You may have to try both and see which one you like better.
If I am going to give my husband head I figure I may as well finish the job and swallow it, even though I hate the taste. Also, make sure the guy showered soon before because sweaty balls reek, and the smell can really be a turn off.