Hi B.,
I'm also a mom of 3 recently under 4. They are now 4, almost 3 and 8 months.
I am a cloth diapering mom but have used disposables on many occasions and have never used the name brands (I've tried samples of them), always the discount ones. I wouldn't see an issue with the Smile's brand ones, and as many have said you can return them if you're not happy.
One thing I have found regardless of what brand I have used is that performance has more to do with how the diaper is put on than the quality of the diaper itself. Except for a very few, all diapers now have an elastic piece just inside the leg. Once the diaper is securely fastened, it's always best to take your finger and run it along the inside of the diaper from the back to the front at the leg and gently expand the elastic as you do that with a finger and "activate" the no leak barrier. LOL. Sounds funny to say, but it always seems to work for me with any brand of disposables, and I have tried just about ALL of them. Since I don't have a Sam's club membership I can't try the Smile's though.
Also, I have found being a cloth diapering mom I think I tend to change diapers on my little ones a lot quicker than most even when using disposables, so I'm sure that in some cases it has made a big difference in the smell factor that some have talked about.
Give them a shot, it couldn't hurt. And I too HIGHLY recommend the White Cloud brand at Wal-Mart. Even the ones in the yellow packaging, I forget what they're called. Very inexpensive and worked great for us.
Good Luck!
Rolinda