I've delivered 2 of my 4 children at SMMC and the most recent was just 1 year ago. I've also had a D&C outpatient at SMMC for a miscarriage. They are still under construction, I believe.
I had a great experience and felt like my OBGYN and labor/delivery nurses were the best!! I had an emergency c-section and a scheduled c-section and both times I felt very confident about the care I received. I think the staff and how you are treated are more important than the size of your room, personally. SMMC is very busy (probably busier than SLS because of location and they've been in the business longer) but I didn't have any trouble getting my needs met. Anesthesiologist was awesome and they have great NICU if you're baby needs it (which one of mine did until she was well enough to transfer to Children's Mercy). Cafeteria is small for family members but the "galley" is great for snacks for you and your hubby.
I also like the "Mommy and Me" store where I could go back and weigh my baby for free, anytime after I got home with her since I was nursing. I wasn't that crazy about the "picture lady" but that's not someone who is employed by SMMC anyway and I complained about her later on when I had more time to reflect and deal with it. There are more resteraunts located around SLS which is a plus if someone is going to pick up food for you but that wasn't that big of a pro for me to go there. I'm comfortable with SMMC and trust them! I'd go there again in a heartbeat if I were planning on more children or any other surgery for that matter.
SMMC also has a "nap time" for new moms/babies every afternoon which was nice because you can participate if you want and that allows you an easy way to say "No visitors" for a short time while you and the baby get needed rest.
I don't know how old your two boys are but they do offer a "sibling class" at SMMC which I took my kids too when we were expecting #3. It helped the kids understand why Mommy was going to the hospital and where I'd be so they wouldn't be afraid. They also got to make the new baby a little gift that was kept at the hospital until the baby arrives.
Wish you the best but just know that sometimes things don't always go as planned no matter what hospital you go to:)