I would highly recommend avoiding alt-coins. And it would not spread the risk to buy multiple alts since they are all based on the same technology. Want to diversify? Buy some bitcoin, gold, real estate, stocks, etc.
Solid advice right here. If I only had $1500 to invest, I most definitely would not buy any altcoins. Bitcoin perhaps, but with shitcoins you might as well take that $1500 and buy scratch tickets or go down to the casino and play poker. Hell, you might as well burn it in a fireplace.
That may sound like heresy on bitcointalk, but right now I have serious doubts as to the future of not only altcoins but bitcoin as well. I think the stock market is looking pretty damn inflated right now, too, but I'd much rather buy a blue chip, dividend-paying stock to hold for years than some altcoin that probably only 200 people will ever own--and own only in the short-term as well. You can kiss that $1500 goodbye investing in that shit.
So my picks for spreading $1500 around: One 1/4 ounce gold coin, probably an American Eagle or something Mexican. $700 worth of Coca-Cola stock in a dividend reinvestment program. And the rest I'd buy bitcoin with. That would be enough diversification for $1500.