Unless you get EXTREMELY lucky and score a set with an error coin, neither set will grow in value significantly ahead of inflation. They are good if you like sets of uncirculated/proof coins, but they have been a poor "investment" since the 1980s--a set bought for $15 back in the 90s might sell for $25 now, but the dollar is only worth about half as much by comparison. Proof sets are more expensive than mint sets, but I'd define "value" as (Price realized) - (Initial cost), adjusted for inflation.
If you are looking for a good "investment", your best bet is to hunt through coin rolls, particularly if you work close to the cash distribution channels. Uncirculated rolls of 2009 coins (especially cents and nickels) will probably see hefty premiums over the next couple decades, and you can make a quick buck on
ebay by selling unbroken mint rolls of coins that are known to have errors and/or varieties.