Hi Emilys,
Welcome to the Mattress Underground.
There are so many mattresses on the market, the important thing to look for is quality components. Quality spring support or latex foam, even HD foam. A comfort layer of natural fibers, latex or HD foam of at least 1.8lbs, and a nice quilted or stretch cover depending on preference.
It so happens we have been sleeping on a Brooklyn Bedding Plank Luxe firmer side for close to 2 years now. I am 6’ 220 and my wife is 5’4 135ish. Quite frankly, absolutely love it! We are both mainly side sleepers, I occasionally flip on my back and stomach for short periods, but the mattress thus far has been excellent.
On the flip side, I bought my 86 year old mother in law a @DLX Premier Hybrid. I ordered it in a firm/med as she was not able to try it first (this mattress is that good, she did not need to try it first, from day 1 to 6 months later, pure comfort). What a nice mattress! I bought her a yawnder4 adjustable base to help her with other aging issues, and the combination was perfect with her at 5’3ish 170ish pounds sleeping on the firm side. This mattress is a bit more expensive than the plank luxe, but does offer adjustable firmness levels, basically forever. If a comfort layer ever fails or becomes out of favor to your preference, you can order another. Now they have HD foam, Latex and Memory foam available to suit a variety of preferences.
Having spent some time at the Vegas Market recently and experienced a plethera mattresses. The are a lot of USA made and manufactured that are worthy of consideration.
When following some basic principles of mattress shopping asking the right questions and working with interested professionals, your chances of finding your perfect match becomes more evident.
The BB Black is only found in stores not on line, but is their attempt to compete with the S/Legacy brands out there. Personally, just my opinion, they do an excellent job in accomplishing that. Much like most of the TMs here do an excellent job of producing high quality, durable, long lasting mattress options.
Buying from an independent BB authorized dealer (as I did) is often a better choice than buying direct. You become an individual and not a number and the independents have a larger stake in making you completely happy and directing you in the right direction to meet all your needs and preferences.
All the best,
Maverick