This is my first ever piece of furniture. I bought the Kreg Jig, which is awesome. My son has a fairly small room, so extra floor space is handy. I plan on turning the bottom into a reading nook with come comfy pillows, some lighting and a few small bookcases.
I used 2x6s to support the mattress. put in 6 slats, but I think I'll add one more for extra support. I also want to add a 2x4 across the back to keep the legs in place. Pretty sturdy though. I got up there with my son and between the two of us we're about 230lbs.
Can't wait to build something else!