No doubt the best alt is litecoin
Litecoin is first altcoin but not the best for sure
Which is the best altcoin then?
It's hard to tell which is best, bet just read specification and compare it, there some a lot more interesting ones with much greater grow potential
What do you define as 'interesting' and 'grow potential'. Majority of these coins are clones of one another and offer nothing new or interesting. Sure, you can jump in early on some and make a little bit, but not even the most popular alts have any decent marketing or ideas behind them.