Yes, I have done an enormous amount of testing with domain names. .org does have a slight advantage over .com, and .com has a slight advantage over .net. They are the only 3 TLD's that get the exact match bonus from Google. .biz and .info get zero exact match bonus in my opinion.
The reason there are still a truckload of .org exact match domains still available is due to Gurus always enforcing that people stick with .com's for branding purposes. Since iv been aware of the exact match bonus for 18months now, iv managed to pick up some rippers. Even just a few weeks ago I picked up nowinnofeelawyer.org and it will blow your mind what lawyers are paying per click in adwords for that exact match phrase. I havent done anything productive with the domain yet other than threw wprobot to get it nicely indexed. Go have a look in the Google adwords keyword tool for the cost per click estimates if your intrigued. Here is a quick example.
no win no fee accident claim - ave cpc = $292 - 2900 search/month
no win no fee claims - ave cpc = $260 - 1300 search/month
no win no fee - ave cpc = $255 - 8100 search/month
I picked up 5 exact match domains from this niche that day, my highest pays out at $130 per click with 4000 monthly exact match searches.
Exact match domains are extremely easy to rank for their accossiated key phrase. Only takes 5 or 10% of the seo and backlinking a normal domain would take. But remember thats obviously only for its exact match phrase. There is still a benifit if you have a domain nofeelawyer.org and somebody searches plural, "no fee lawyers", but that benifit is only a fraction of what the exact match bonus is, so would take a lot more work to rank.
Ill do some round about calculations for my domain. Lets say I get it to number 1 ranking in Goog and get a 50% click through rate to my website. So 50% of the predicted 4000 monthly searches for my exact match term is 2000 visits. With most of my developed adsense monitized exact match domains I get between 15 - 30% CTR on my adsense.
Nobody knows because Google wont tell, but adsense gurus believes we as adsense publishers get around 60 - 65% of the value of the adsense click.
So lets say I get a 20% CTR on my adsense with this new domain, Google pays me 60% commision on every click, each click is worth $130 x .60 = $78 per click
2000 x .20 = 400 x $78 = $31,200/month, jeez thats not bad eh, haha.
I very much doubt I will get $78/click due to other content on the web page diluting the value of the clicks but still, its definitely got potential and the 4 other exact match domains I picked up from that niche that day are not far off it either.
Hope those ridiculously high numbers inspires you to go out and get some high search volume, high cpc exact match domains for yourself. You will be amazed at how many pots of gold are still available. Get into it.