By rates I guess you mean fees. Vanguard is usually cheapest. If you meant returns, you better not look at past performance because it's not a solid indicator. I'm a fan of contrarian investing (buy low sell high...suprising some people aren't) with Modern Portfolio theory. Don't let anyone tell you they can invest money better if you pay them more. Go with index funds.
Generally with returns in the next 40 years, expect 10% for small cap value, 9% for large cap value, 8% for large cap growth, etc you can look that up but that's not definite either. You can boost the returns through MPT and rebalancing while reducing risk. If done right, you should expect 12-4% in the long run.
Since it's taxed sheltered, it's more suitable for certain asset classes than others. Like small cap because there's more trading there's more taxes. But because it's tax sheltered, you're immune. If anything is not in a tax shelter, put it in something like a large cap index fund.
You need to know what kind of portfolio you want to compose. I'd recommend mostly index funds or low cost mutual funds from places like Vanguard. Then rebalance according to portfolio theory.
If you want to take it conservatively, you may want to start with a balanced mutual fund. Wellington is best because it's value, but they've just upped the minimum contribution to 10,000, so you're second best choice is STAR, which is large cap blend with a minimum of 1,000.