Sleep Number beds are pretty good BUT...there are a few things you need to know before you make the purchase.
First, if you like a firm mattress, Sleep Number is great because you can keep it firm over time. Second, if you like a firm mattress and your co-sleeper likes squishy, well, you've seen the ads. That stuff you probably figured out.
Here's what you may not know: Sleep Number with no foam on top is hard as a rock no matter how low you set your number. So, be prepared to add a mattress topper. The good news here is that if you bought the thin Sleep Number, like I did, sheets will still fit over it. The bad news is that you are going to struggle finding one that doesn't make you sweat and you'll need to replace it every 3 years or so. There are models that have a thick foam top and that's supposed to eliminate the need for a separate topper. But, foam compacts over time so if you get that model, you are right back into the short lifespan of a standard mattress.
Finally, Sleep Number beds will need to have parts replaced. You're going to need new air bags, hoses, and a pump. It will happen a lot sooner than the advertising leads you to believe. And, while you wait for these parts to arrive on your doorstep, you're going to be sleeping on your couch. So, you may fall in love with your Sleep Number the first week you sleep on it but be aware that you are going to spend about $200 every other year on parts. We've had ours for 6 years. We've spent $800 on two mattress toppers, one replacement air bag and a replacement pump. Warranty? Yes. That's with the warranty.
Bottom Line: No, I would not recommend this to a friend