Costco vs. Sam's Club

Recently we got a membership to Sam's Club. We already have Costco, but Glade needed some stuff at the other for work. I have been twice and I can't exactly decide what I think. Here is the best I can come up with:

-Some things are more at once place than the other and vice versa - no real help there
-Costco gives 2% cash back
-Costco's gas was cheaper
-Sam's Club is much like Walmart (duh) but what I mean by that is that the help is the same caliber, sorry if that is snobby.
-Sam's Club membership is cheaper
-I THINK I would save money in the end if I shopped at Sam's Club, but not positive. If I did, it would be minimal.
-Lastly, Costco's pizza is much better.

Was that helpful? I didn't think so. I prefer Costco, but it might be slightly more expensive. The thing I noticed is that Costco was cheaper than Sam's in a lot of areas, but when they weren't, it seemed like they were way more expensive. For example: Kellogg's fruit snacks were $4 more at Costco and Huggies were $6 more. That's a big difference. So I guess if I were diligent and paid attention and took the time, I would just shop both. I don't know, that sounds like a pain. I'm still comparing, I'll let you know if I come up with anything conclusive. Anyone have any opinions on the matter?