Now I read this bit I'd say it might be best to get your tunes into some of the top jock's boxs/CD wallet. If they play it out then it should build some momentum & make some sales, get you gigs etc.You never know, one of said Jocks might want it on his/her lable. You could just approach SUF direct.
I think the days of having a 1 off really great tune to get you credibility might be over cause of the ammount of tunes out there & the changes in the music industry over the last 10 years. Just cause you've got a tune onto beatport doesn't mean you can get to a really wide audience. I think its usually more down to leg work like putting good club nights on, playing loads of DJ gigs, producing with other artists etc that get you crediblity & a good fan base these days.
Regarding download sites, I think Juno & Beatsdigital are a bit easyer to get your tunes on & are maybe held in better regard by people into underground music. Beatport are quite strict on who they will put on there, its more based on sales than quality & you usually need to be an established artist. Quite a lot of folk who are into underground music boycot them for that reason.
Good luck with it all anyway.