ACWW is the only Wi-Fi game whose Wi-Fi is not the only thing that keeps replay value. Wi-Fi is more of a gimic than a needed reply value keeper (like in MPH and MKDS). Both are good games, but I think ACWW is more fun. 3+ months vs. 3+ days, what would you get?
ACWW: Great game IMO. Great replay value, the Wi-Fi gimic, great idea for a game, orginal, and as boring as it looks, is fun.
NSMB: Great game all-around, except for two things:
1.) If you played SMB1-3, you will see they just pretty much copied old courses.
2.) Pratically no replay value due to the fact difficulty is lacking.
So really, it comes down to replay value, hands down, this is probably ACWW's high point.