Hi Pearsall,

I've had both the 5T's and 6T's, but not the 6B's. My room is approximately the same size in sq feet (22x14x10 = 3080). I had the 5T's for 8 months and decided to upgrade to the 6T's because I wanted to use the year trade up program. I sit 12 feet away from the towers and I can tell you there is a substantial difference between the 5T's and 6T's. The 5T's are great....the 6T's are amazing. Even if you wish to cross them at 60hz (like I do) or 80hz (per thx) you'll notice a substantial difference in the mids between the two sets with the 6T's having a fuller midrange. I haven't heard the 6B's but the reviews are equally great. Remember you can test them yourself for 30 days risk free. 

Hope that helps,

Jason