I tend to be leery about Ebay breaks. Now breaks on trading card forums and from card bloggers I'll join in every now and then. But I only do ones where I can pick at least my first team. I don't do any of these totally random breaks, because I don't want to be stuck with a team I hate and in each sport I have at least one team I hate. I have only bought into Baseball and Football Breaks, Some years back I blog hosted a Basketball (the one Billy mentioned) break, and a Baseball break. Due to the work a beaker must do (prep work for the break, video host sites to do the break on, sorting of cards and sending out and much more) to be fair and have a successful break, not to mention the cost of shipping now-days I have no plans to host any other breaks.
One thing to look into when thinking of joining them is to see if you get all cards of your team or just the "hits". Some breakers consider inserts and parallels to be "hits" but most do not, just the autos and relics (maybe printing plates if the brand includes plates as hits). Many of the forum and blog breakers will send you all cards of your team from the break including duplicates and multiples, unless you request no duplicates or no base.
Also consider what product is being busted. A High End product might only be 1 pack of only 5 cards for the entire box. Not a great break to enter into. If your team is a below average team it might not be included in some of the cool inserts.
So before getting into a break RESEARCH everything from what product is being busted to the break host and their "rules" or guidlines for the particular break you are interested in. If possible check out previous breaks from the host as well to see how they show stuff in the video
I collect: Baseball, Football, Hockey, Mostly Vintage pre1980, My Homie teams - Washington/Baltimore Teams Senators (Twins, Rangers), Expos/Nationals, Redskins, Capitals, Bullets/Wizards - HOFers - Non-sport (mostly TV shows and movies).
My Trade List is very much a work in progress
CaptKirk42s Trading Card Blog Curly W Cards Strive For '65 YouTube klandersen42