Hi MatrixClaw,
You certainly made a high quality/value choice … and congratulations on your new mattress 
[quote]We have it set up as follows:
Bottom: Metal bed frame
Middle: Boxspring from old mattress set
Top: Tuft & Needle mattress
Topper: Mattress Pad
Am I doing something wrong? I don’t really want to have to buy another memory foam topper just to make the mattress more comfortable - if that’s the case, I’ll just go back to the old mattress and save myself the $600 I spent on the T&N :([/quote]
No you certainly aren’t doing anything “wrong” but any particular mattress won’t be good match for everyone that purchases it and this is the reason that a trial period can be important with an online purchase.
Having said that … there are a few suggestions that may be helpful.
First of all … there will be an initial break in and adjustment period with any new mattress over the course of the first few weeks and your sleeping experience will change as the mattress softens up a bit and you also get used to a sleeping surface that is different from what you are used to (see post #3 here).
There are also some suggestions in post #2 here that may be helpful. I don’t know what type of mattress pad you have but it’s very possible that it could be interfering with the ability of the foam layers to contour to the shape of your body which could be firming up your mattress. It could also be contributing to your sleeping temperature as well. You can see an example of the difference that removing a mattress pad can make in post #231 here and in this topic.
Of course each person has their own definition of firm and soft and what feels too firm for one person can feel too soft for someone else (or vice versa) so if the mattress is still too firm for you after a few weeks then at least you had the foresight to purchase a mattress with a great return policy so you could try it in your bedroom instead of a showroom without any risk.
Phoenix