You seem to be in a similar situation to this one. Perhaps wanting a little plushier, but you need to be careful you dont sink down. Perhaps the latex version of a few of these mattresses so you dont sink, as latex will better than memory foam in that regard. Take a peek at some of the suggestions above.
Also, for a similar “feel” of that BR 3 mattress, take a look at the Brooklyn Bedding Titan Plus Elite. Although the Titan Series is designed around plus sized folks, when at the trade show, it was so comfortable (even though we like super firm) with the eurotop comfort layer, with the microcoils to keep cool, I got one for my guest room. Pricing is probably more where you want to be and the placement of the micro coils are better than the BR. The BR has a lot of comfort layer above their nice spring support, over 8" which sometimes undermines the function of the spring support causing the mattress to sink prematurely. Sometimes you have to wonder if they are just charging more making the mattress taller, it is almost 17." They have already changed the name of the series from letters to numbers to move away from the stigma that the letter series caused.
Maverick