I think that the Brazilians truly changed the complexion of how we look at HtH in this day and age. They have some great stuff and several are excellent teachers. What you must be careful of though is; a number of the Brazilians coming to the US are sport oriented only. They will all tell you they have a NHB background, but in reality they have very very little. A sport guy is very happy to keep someone in the guard forever, thats a way he gains points. As I beleive Rob said, for LEO's that shouldn't be our goal. Ground skills (as well as striking, and firearms and impact weapons) are essential skills. But keeping in mind the restrections associatied with those skills. Rolling around on your back, with a big drunk wife beater on top of you, with 30 extra pounds of gear makes for intresting training. On the same standpoint, I'd rather have that training than none at all.
A second issue. As with Koreans in the 60's, if you say your from Brazil and speak Portuguese, you must be a jiu jitsu instructor. Let the buyer beware. Some of these guys are here for a quick buck and as soon as the flurry over BJJ is over(I think its dying already) they'll be outa here.
On the positive note, what the Brazilians did (and specifically the Gracie family) is take a grappling sport (turn of the century Kodokan judo) and transform it to have street fight capabilities. From this hybrid systems have formed and will continue to.
I think we are on the edge of knocking the dust off of the perception of combatives in this country. Systems for their original purpose, fighting. Not to collect medals, or find one's center, or to be a tv star. To some those are worthwhile goals and they should be pursued. But the hard reality is, several of us want to and need to be proficient in combat, with whatever course we take.
Bruce Lee said "all knowledge is ultimately self knowledge". We draw from our experiences and make that learning the most effective tool to reach our goal.